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Aplusclick Grade 12 Questions
The first person is 100 cm tall. Each subsequent person is 20% taller than the . . .
The last digit of the number 7
77
is
Find the hundreds digit (third digit from the right) of the product: 44444 x . . .
Which gives the largest answer?
Which is the sum of all digits of the decimal representation of 5
16
. . .
The sum of the digits of a two-digit number X is Y. The sum of the digits . . .
Which gives the largest answer?
How many three-digit numbers have exactly five divisors including 1 and itself?
Make two fractions with all the digits from 0 to 9. Use each digit once. They . . .
What is 2 to the power of 16?
If you wrote all the whole numbers from 1 through 1000, how many times would . . .
With a 1 after a nine-digit number, it is the same as a 1 before it. Find . . .
I multiply the two page numbers and get 6162. What is the right-hand page . . .
What are the two last digits of the result? 1999999991 x 2000000009
If X
Y
= 1024 and both numbers are integers, which of the following . . .
Which number is smaller than the sum of its divisors other than 1 and the . . .
Which numeral system states that 7 + 6 = 15
How many digits are there in the number 625
10
? Please don't use a . . .
Which of the following gives the largest result? Do not use a calculator.
Savin's problem: Using each of the digits 1,2,3, and 4 twice, write out an . . .
What gives the smallest result? Here we write 0.333 . . . as notation for . . .
What is the sum of the first 100 prime numbers? A prime number is a natural . . .
The average of 99 consecutive numbers is 99. What is the average of the nine . . .
The natural numbers are the counting numbers, like 1, 2, 3, et cetera. An . . .
0.999 . . . means infinitely repeating decimals. What is the largest result?
A magic square is an arrangement of integers, in a square grid, where the . . .
Leslie Green asks: What is the next number in the sequence? 0, 3, 1, 4, . . .
Shakuntala Devi was undoubtedly the most brilliant arithmetic mental calculator . . .
Choose the condition when the inequality (2 + n)n > (1 + n)n is always true.
Which of the following points lies on the line 3x + 4y = -12
Line AB has the equation y = 0.5x + 3 Line CD is parallel to line AB. . . .
Which equation describes a line of symmetry for the shape?
Find the center of the prism with the following vertices. A(1,1,1), . . .
Which of the following graphs represents all values of x, such that:
How many digits are in the result of the expression? 1001
11
Which of the following gives the biggest answer?
If y is the fraction of the white area of the square, which graph shows the y . . .
How many integer values of x are the solutions of these two inequalities?
Find the point of intersection of these two lines.
Which equation represents the axis of symmetry of the graph of the parabola?
Three points of four are on a line. Which point is not on the line?
Xia and Yvonne collect buttons. Xia only collects the ones with two holes and . . .
Ten teams enter a basketball tournament. Each team plays one match against . . .
How many points of intersection do these three rays have?
A square game board begins with a dark square alternating with light squares. . . .
Which function gives the angle in degrees between the hour and the minute hands . . .
Find Y.
Estimate the ratio of the large rectangle width to height if the two rectangles . . .
How many solutions are there for X?
A swimming pool is 12.5 x 8 x 3 meters. The average volume of a human body is . . .
In an examination, there were 4000 candidates, of which 2200 candidates were . . .
A tree increases its number of nuts at the rate of 100% every year. What was . . .
What amount of water should be added to reduce 200 milliliters of 5 percent fat . . .
A car starts traveling at an initial speed of 120 km per hour (kmph), the . . .
What are the smallest and largest integers that will make this expression true?
Evguenia walked to school. Twelve minutes after she left, Sasha started. His . . .
There are 190 coconuts in a basket. Sailors one after another take out half of . . .
The weights of each pair of these boxes are 98kg, 101kg, and 102kg. What is . . .
Mike’s age, M, is equal to the sum of the ages of his four children. His age N . . .
Two trains, each 400 meters long, pass each other completely in 10 seconds when . . .
Two tourists paddled downstream for 2 hours and then upstream for 4 hours. . . .
A group of 22 scouts goes on a trip. They prepare enough food to last 18 days. . . .
The Smith family consists of parents, children, and animals. Some of them are . . .
In a city, sixty percent of the men are married to eighty percent of the women. . . .
"A coach leaves London for York and another at the same moment leaves York for . . .
How many "yes or no" questions are needed to guess any 5-digit code?
A series of 10 books were published at two-year intervals. The sum of the . . .
The product and sum of two positive integers X and Y are added together. The . . .
In a recent election, 1111 people voted for two parties. If the ratio of the . . .
The wind in the open-air swimming pool increases the westward swimming speed . . .
Find x.
X + XY + Y = 34 Find all positive integer solutions of the equation, for which . . .
What is the sum of the squares of the whole numbers from 1 to 10?
Divine the value of the Divine proportion AC.
The balance is in equilibrium. Find Z.
If 3 pens and 5 pencils cost as much as 5 pens and 2 pencils, by how much is a . . .
Gerry and Jane are exactly 100 km apart. Gerry leaves his place running at 10 . . .
How many pairs of prime numbers add up to 101?
The occupancy percentage of a hotel is 64% for the four summer months and 46% . . .
0.123123123123123 . . . . What fraction is it?
Water increases its volume by 1/11 when freezing. By what part of its volume . . .
If the sum of two numbers is 9 and their difference is 11, what is their . . .
Two men and two women want to cross a river. The boat will only hold one man . . .
The stand-in mathematics teacher is forced to choose two students to go on a . . .
Leslie Green asks: Given Cartesian axes of infinite extent, find the ratio . . .
Find the ratio of the areas above and below the parabola y = . . .
A grocery store sells Brazilian cacao in 15-kg bags and Ecuadorian cacao in . . .
A cube is painted on the outside and then divided into one-unit cubes. The . . .
Which of the following is equal to fourteen divided by nine?
There are 1000 students in a high school. 20% of girls and 30% of boys were . . .
A fence around a rectangular garden has a perimeter of 14 meters. Its length . . .
The volume of water in a glass of V cubic centimeters (cc), varies directly as . . .
Tim travels 15 meters north of the flag in the football stadium. He turns . . .
S varies directly as the square of (H+1) S = 121 when H = 10 Find H when S = . . .
A rectangle has width W, length L, and area A. If integer W ≤ 9 and L . . .
A wire is wound around a circular rod. The wire goes exactly 5 times around . . .
Which is the best estimate of the area of the colored shape?
These two shapes are similar. What is the length of x?
Identify the area of the rounded square.
A boy stacked colored cubes in a square pyramid like the one shown here. The . . .
A six-pointed regular star consists of two areas. What is the ratio of the . . .
The figure shows a red equilateral triangle inscribed within another . . .
If the volume of a cube is X cubic meters and the total surface area of the . . .
The side of the colored square is x cm. What is the area of the red . . .
The three circles have fixed centers, and the diameter of a circle is 10% less . . .
L3 and L4 are two parallel lines in a plane. If L3 has 3 points equally . . .
What is the total number of lines of tangency that are common to circle C1 and . . .
For this rectangular-faced solid (cuboid), which plane(s) contain(s) B and . . .
Two similar pyramids have volumes of 216 m
3
and 64 m
3
. . . .
AB is parallel to CD. What is the value of X?
There are 2 identical circles. Circle A remains fixed, while Circle B makes 1 . . .
G is the area of the green region inside the biggest circle. R is the total . . .
The area of the external triangle is equal to 1. Its sides' midpoints are . . .
The pattern of shading in one quarter of a square is shown in the diagram. . . .
What is the maximum number of squares you can make using twelve identical . . .
A gardener has to reach the island in the middle of a pond without getting wet. . . .
Three reservoirs have the same height h=1. Which reservoir is bigger?
What is the largest semi-circle that can be inscribed in a square with a side . . .
Twenty matchsticks form five squares (one 3x3 and four 1x1). How many . . .
A ladder leans against a vertical wall. The top of the ladder is 4m above the . . .
If the length of the hour and minute hand of a clock are 3cm and 6cm . . .
All inner lines connect the corners of the big square and the midpoints of the . . .
A square is inscribed in a right triangle. Find the greatest possible ratio . . .
What value of X gives the greatest ratio of red area to the area of the big . . .
Among the following shapes of equal area, which has the smallest perimeter?
The sizes of the sealed bottle with water are shown in the figure. Find the . . .
How many equilateral triangles can you make using six identical line segments?
The following pattern is cut and folded to a square-based pyramid. What size . . .
John is using the spinner shown here to define the movement. Blue means one . . .
How much wrapping paper is needed to entirely cover a box that is 40 cm by 30 . . .
What is the ratio of the green area to the red area?
Four squares have dimensions as indicated in the picture. What is the area . . .
What is the maximum number of possible points of intersection of N different . . .
The diameter of one hair is 0.2 mm. Estimate the diameter of a plait of 1000 . . .
Two lines trisect (divide into three equal parts) each side of the polygon . . .
The shaded rhombus is formed by joining vertices of the square to the midpoints . . .
The diagram shows 15 billiard balls that fit exactly inside a triangular rack. . . .
The picture shows the areas of three rectangles. What is the area of the . . .
Two triangles form seven separate regions. What is the greatest number of . . .
There are six ways to travel from point S to point F on a small cube if only . . .
Estimate the area of the smallest square that can enclose the regular hexagon . . .
A, B, and C are squares with sides of length 1; D, E, and F are isosceles . . .
I drew three lines from the center of a square that has sides with a length of . . .
What is the maximum number of pieces that an apple can be divided into with . . .
Each of these five circles is tangent to at least 3 others. The medium sized . . .
Find the radius of the circle.
In a city, there were seven bridges. There was a tradition that a newly . . .
A sphere fits inside a cube. The maximum possible ratio of the volume of the . . .
I want to cut a wooden cube that is five inches on each side into 125 one-inch . . .
What line divides the green polygon into two parts of equal area?
I need 1 + 4 + 9 + 16 + 25 = 55 cubes to build a pyramid with a height of 5 . . .
I want to place N cubes so that each cube touches every other one. What is . . .
What is the volume of the second glass compared to the first one?
The Babylonians used a base 60 number system. What shape inspired them to . . .
Connect N points on the circumference of a circle. What is the largest number . . .
I take a map of the city where I live and lay it on my table. There is a . . .
What is the largest number of intersections of N lines?
I connected the midpoints of a polygon and constructed a new polygon that was a . . .
A pyramid and a tetrahedron with edges of the same length are glued together on . . .
I need 1 + 9 + 25 = 35 cubes to build a pyramid with a height of 3 cubes. . . .
Inspired by Boris Kordemsky. Four Knights problem: Cut the chessboard into . . .
Which shape is more symmetrical (i.e. has more planes of symmetries)?
How many 1x1 squares fit into the large square with the side length 4.8? . . .
What is the greatest possible number of points of intersection for 11 lines in . . .
The picture shows three squares with the side lengths of 10, 8, and 4 cm. What . . .
A trapezoid is formed by cutting off the top part of an isosceles right . . .
If regular stars are placed as shown to form a complete circle, how many stars . . .
What fraction of this regular octagon is shaded?
The stripes have the same width. What part of the square is red?
A circle goes through two adjacent vertices of a square and it is tangent to . . .
The figure shows adjacent squares. Find the sum of angles X and Y.
A helicopter takes me from Lausanne, Switzerland to the Swiss capital Bern in . . .
What is the probability of breaking a stick into three pieces and forming a . . .
What is the maximum number of trees that can be planted, not closer than 3 . . .
A rectangular yard with an area of 24 m
2
has sides in the ratio 2:3. . . .
Which triangle has the greatest area?
Which is a better fit? The smaller the percentage of the ‘area left over,’ . . .
Two perpendicular lines form four segments with lengths a, b, c, and d. . . .
The size of an NBA basketball court is about 29 by 16 meters. How many . . .
How many pentagons are there?
The golden border of the hexagonal brooch with maximum size 60 mm includes a . . .
What is the maximum number of sections into which a pancake may be divided by . . .
If I use 30 g of batter to make a crêpe of 30 cm in diameter, how much batter . . .
The numbers show the areas of corresponding triangles. What is the area of . . .
What is the perimeter of a right triangle whose shorter sides are 9 and 12 . . .
The picture shows a large cube 4 x 4 x 4 that was assembled from one-unit . . .
What is the largest number of straight lines you can draw through 9 points, so . . .
John cuts a large piece of cheese into small pieces using straight cuts from a . . .
Gerry has 24 meters of fence and wants to make a rectangular garden with the . . .
Find X.
Take two sheets of A4 paper (210 x 297 millimeters or 8.3 x 11.7 inch). Roll . . .
Two right-angled triangles have integer side lengths. Whilst all of the sides . . .
Estimate the maximum number of smaller 1-inch circles that fit in a larger . . .
There are two paths in a rectangular garden. Find the length of the shorter . . .
My garden fence creates a ten meters by five meters rectangle. If I reuse all . . .
Which shape has the smallest perimeter?
What is the largest distance if the angle B is right?
Three semicircles are constructed on the hypotenuse and legs of a right angle . . .
There are 3 circles of equal diameter. A line is tangent to the third circle, . . .
There are 2 different data sets. Set 1: 1, 3, 7, 9, 13, 15 Set 2: . . .
Anna has 3 bags of marbles. The first contains 5 white marbles and 5 green . . .
Tom has 3 bags of marbles. The first contains 4 white marbles and 6 green . . .
If the area of the left triangle is 100%, what is the area of the second . . .
John has an average of 89 on his three math exams. To earn an A, he must have . . .
I roll two dice. What is the probability that the second number is greater . . .
How many different 7-digit phone numbers can be used by a phone company? The . . .
The table shows the results of a competition among 5 teams. Each team plays . . .
As each of five eggs is weighed, the average weight increases by one gram each . . .
The probability that two randomly chosen people in a big city are younger than . . .
In a game, you have a 1/5 probability of winning $100 and 4/5 probability of . . .
What is the average of these numbers?
John is sick 6 days per year. The probability of being sick on a Saturday or a . . .
This formula, developed by Austrian mathematician Richard Von Mises, shows the . . .
Five people sit at a round table. What is the probability that they sit in . . .
This formula, developed by Austrian mathematician Richard Von Mises, shows the . . .
A boy begins walking from his starting point. Each hour, he either walks one . . .
What is the units digit of 1! + 2! + 3! + ... + 2011!? 4! means 1 x 2 x 3 x 4
Abbey has a dog Abby. She places 5 tiles with the letters of her surname into . . .
Two princes and two princesses are ready to marry. Everybody independently . . .
I randomly place three crosses into different cells of the grid. What is the . . .
A 4-character password uses exactly two different digits. Each digit can be 0, . . .
After a rodeo, four cowboys have a meeting in a saloon. Each cowboy has only . . .
Two dice are thrown. Two numbers are multiplied. What product of numbers . . .
What is the average of the smaller of three random numbers from 0 to 1?
How many seconds were in 2012?
What is the sum of all 5-digit integers which each use all of the five digits . . .
Make 727 by using three 7s. You can use any math operator that you would . . .
Anna (A), Bill (B), Cindy (C), and Daniel (D) work on a project. (1) . . .
A venture capitalist has choosen to invest in only one of three start-up . . .
How many different cubes can I make by using six different colors such that . . .
In a venture investment fund, all investors continue to invest into a new . . .
Logic puzzle: Counting down from 100 by one, which number comes next?
What is the probability that two dominoes drawn randomly from a standard set . . .
Tom has 3 bags of marbles. The first contains 4 white marbles and 6 green . . .
Alex received a 90 on his essay and an 80 on his final. He got a 90 on class . . .
This picture shows the first five rows of Pascal's triangle. What is the sum . . .
What is heavier than a cumulus cloud, which is about 1 cubic kilometer in . . .
Eight bugs are at the eight corners of an equilateral cube. Each bug randomly . . .
Logic question. What is the easiest way to make the following equation . . .
A chess queen attacks all squares along its path horizontally, vertically and . . .
We want to merge 4 companies into one large company. How many ways are there . . .
Find the sum of the series: 1/3 + 1/9 + 1/27 + 1/81 + . . .
What is the average of the largest of N random numbers from 0 to 1?
I want to find the smallest number divisible by 225 that consists of ones and . . .
Place the cards into two boxes so that the probability of randomly drawing a . . .
Alex possesses 52% of a business and the rest belongs to Bill. They take . . .
Find the infinite sum: 1 - 1 + 1 - 1 + 1 - 1 + 1 - 1 + 1 - 1 + . . .
A player must match three different numbers chosen from the integers 1 to 30 . . .
The picture shows a subway map. If it takes 3 minutes to go from one station . . .
In a country, a baby is born every 5 seconds, a person dies every 45 seconds, . . .
This is a standard set of dominoes. Choose 2 dominoes at random. What is . . .
A concert includes 3 cello pieces and 3 piano pieces. In how many ways can . . .
Anna and Bill roll a six-sided die. The first person to roll a six wins. Anna . . .
You can throw as many darts as necessary at the board shown in the picture. . . .
You roll two dice. Estimate the expected value on the highest valued die?
John threw 8 fair dimes and Mary 9 dimes. What is the probability that Mary . . .
Estimate the total you pay if the meal costs $29, the tax is 5%, and the tip is . . .
John and I have a glass of milk. He drinks half of it and then I drink half of . . .
Five students Anna, Bill, Craig, Daniel, and Eugene commute by bus. Every . . .
Find the product of 111,111,111 x 111,111,111
If the probability of observing a white car in 10 minutes on a motorway is . . .
Estimate the probability that no two of four sisters were born in the same day . . .
How many squares are there on a chess board?
The sum of the integers from 1 to 2,000 inclusive is 2,001,000. What is the . . .
My car can travel 20 km on one liter of gas on the motorway and 12 km on one . . .
A 512-page book weighs 800g to the nearest 10g. What is the weight of 200 . . .
When 4 coins are tossed, what is the probability that exactly 2 are heads?
The sum of N consecutive integers is S. Which of the following equations gives . . .
Veryfast Airlines loses 20% of the luggage. Gerry puts his three favorite toys . . .
How many 3x3 squares are there on a chessboard?
95.8% of James' classmates have different numbers of hairs than he has. How . . .
A ball rebounds half of the height from which it is dropped in a sport hall. . . .
When Jane plays against Gerry in her favorite game, the odds are 5 to 3 that . . .
Six dice are thrown. What is the probability that at least three of them have . . .
James the Mathematician wants to find a partner for a serious relationship. He . . .
Steve wonders "Why don’t I have a girlfriend?" He uses the following . . .
Gerry's income is seven-eighths that of Jane. Gerry's expenses are . . .
Which number goes next? 1 1 2 3 5
The cost of living increased in the first year and it decreased in the second . . .
I got a total of 120 by using five zeros and any mathematical operators. How . . .
If you choose an answer to this question at random, what is the probability . . .
How many ways can five runners take first, second, and third place in a . . .
I bought a 20'' (the diagonal size) laptop with the ratio of the screen width . . .
I throw a coin on a chessboard. The diameter of the coin is a half of the side . . .
Gerry's favorite digit is 7. What is the probability that there is at least . . .
I put red and white chocolate candies into a bag. I randomly took 2 candies, . . .
Coin landing on its edge
I flip a fair Swiss franc* and it falls in . . .
I roll two dice, one with the left hand and one with the right. If the left . . .
Leslie Green asks: Criminal gangs have been known to pay vagrants to search . . .
Jane was a naughty little girl. When she used to play 2-dice games with her . . .
Gerry tosses 2 coins and Jane tosses 3 coins. What is the probability that . . .
There are 9 houses on a street. The distance between any two adjacent houses is . . .
Martin has ten thousand dollars in the Mad Money's bank account. The interest . . .
A team of two geeks, Jane and Gerry, independently answers true-or-false . . .
Einstein, the hyper-intelligent house cat, is busy walking from one corner of a . . .
Anton, the highest IQ house ant on the planet, is taking his regular nocturnal . . .
Martin, the mathematical mole, has dug an extensive network of underground . . .
Marek, the pan-dimensional super being, has arbitrarily defined his current . . .
Twenty Knights sit around the Round Table in the following order: 1. King . . .
In what numeral system is the phrase correct?
8 + 8 = 10
Leslie Green asks: quot; The sinusoidal waveform shown has a peak amplitude of . . .
Christmas is getting near, and a four person company wants to run a Secret . . .
What are the odds of getting at least two tails in a row if you flip a dime . . .
Evguenia's teacher assigns 24 math problems to solve. She sorts them from the . . .
Mr. Smith can read 1 page in 2 minutes. His wife can read 2 pages in 1 minute. . . .
The twins are the same height. They place four identical blocks as shown in . . .
How many two-digit integers are there in which the sum of the digits is equal . . .
Ten years ago, Bob was three times as old as Anna. Today, he is twice as old . . .
Statement 1: There are 3 animals in a room. Statement 2: All of the animals in . . .
How many straight lines are needed to separate each star from all the others?
Two gears, one with 11 teeth and the other one with 18 teeth, have teeth marked . . .
1. At least 1 of these 6 statements is false 2. At least 2 of these 6 . . .
You take half of the syrup and mix it with the water, and then take the same . . .
A hunter met two shepherds, one of whom had three loaves of bread and the . . .
In-Out Machine transforms 111121 into 100. The same machine transforms 121244 . . .
An analog clock loses 15 minutes each hour. If the clock is set correctly at . . .
What is the largest number you can write with just two different digits?
Sixteen European teams enter a football tournament. Each team plays one . . .
The product of 2 integers is 1000. Find the smallest possible sum of these . . .
A lady, attempting to avoid revealing her real age to her husband, says: I'm . . .
The addition shown here has 21 terms and the last element consists of 21 9's. . . .
I put $990 into 10 envelopes. I try to compose all possible whole amounts . . .
If 12 workers take 7 hours to build a brick wall 21 m long and 4 m high, how . . .
Alex has bills of different dollar values. There are five times as many ones . . .
On January 1st, Anna and Bill have $100 each. Each month Anna saves $10 more . . .
Four painters can complete a painting job in 20 days. 12 more painters join . . .
Anna bought 1 slice of mushroom pizza and 2 slices of cheese pizza for a total . . .
There are a number of apples, all of different weights. The 10 lightest apples . . .
John has just had a 1% net pay rise. He used to take home $5,000 a month. He . . .
Which of these diagrams could be drawn without taking the pen off the page and . . .
Each of these seven cells contains one number from 1 to 7, using all seven . . .
Multiply all positive two-digit numbers. How many zeros are there at the end . . .
You have four piles: three piles with real coins and one pile with fake coins. . . .
How many zeros are there at the end of
100!
?
Use each digit, 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, exactly once to form two . . .
A bee crawls along the sides of the honeycomb hexagons. It has moved from . . .
How many three-digit numbers containing only even digits are divisible by 9?
On a 5 × 5 grid, I place a 1x2 card so that it exactly covers two squares. I . . .
One hundred and thirty shareholders decide to buy 30,000 shares of company A. . . .
A project manager has to determine whether to purchase or rent four cars for a . . .
Which number comes next? 2, 12, 1112, 3112, . . . .
I want to measure exactly six minutes from the moment I touch an hourglass, . . .
Logic puzzle: a secret door. A man approached the door of a secret . . .
One hundred soldiers form a 10 x 10 square. From every column, the tallest . . .
A donkey must transport 900 carrots to the market, which is 300 miles away. . . .
I arrange five marbles randomly in a ring. There are two green and three . . .
You have a part of a black-and-white map of a reef coast. You are at point A . . .
In any 24-hour period, how many times are the digits of a 24-hour digital clock . . .
Alex greeted Bill. Bill greeted Cindy. Alex did not greet Cindy. If the . . .
Kevin cleans rooms in a student hostel; he earns twice as much for cleaning a . . .
There is only one correct answer to the question below. Which answer is . . .
After a three-hour drive, I stopped my car in front of a wall with three doors: . . .
Divide the circles into two disjoint groups so that the sums of the numbers in . . .
I drive to my country house at a constant speed of 100 miles/hour. I . . .
Anna, Beatrice, and Cindy run a 2000-meter race. All of them run at a . . .
Bob earns $48,000 per year and has two weeks of paid vacation. He works five . . .
"Three sailors come across a pile of coconuts. The first sailor takes half of . . .
There are 12 people in a village. They consume 12 coconuts altogether. Each . . .
Vladimir Arnold (1937-2010), one of the greatest 20th century Russian . . .
A committee consists of 7 people. The committee keeps an important object in a . . .
Thinking outside the box: Which statement is correct?
Thinking outside the box. Solve this:
Which number goes next? 1 3 6 10 ?
Which symbol goes next?
Mr. Rapid always starts driving on a road at exactly 7:00 a.m. If he drives on . . .
On an island, three-quarters of the men are married to four-fifths of the . . .
Working alone, Mr. Smith earns the family's monthly budget in 40 calendar days. . . .
The rear tires of a car wear out after 40,000 miles, while the front tires wear . . .
There are 123 part-time employees and 321 full-time employees in a company. . . .
Students at a school are on average 165 cm tall. The average male student . . .
Mary can complete an activity in 40 days. John can complete the activity in 50 . . .
Find the logic: 12345678 rarr; 4 234567 rarr; 2 . . .
How many uninteresting numbers exist? The question is based on the . . .
A 44-month long project is divided into three consecutive activities. The . . .
Sixteen teams enter a football tournament. Each team plays one match against . . .
"This is a capital letter of the alphabet that's been folded just once. Which . . .
Two trains are 1 kilometer apart on a single track railway line. They set off . . .
If each coconut is priced at $9, then the shopkeeper loses $11. If each . . .
Two successive increases of 25% and 25% are followed by two successive . . .
If Gerry gives Jane one apple, they will have the same number of apples. If . . .
At the end of each week, Gerry forgot 50% of what he knew the week before. At . . .
After an hour, Evguenia catches and frees 10 fish. If there are 100 fish in a . . .
Guess!
What is the word coiled inside this circle?
I choose a 4-digit number in which the first digit is one-sixth the last, and . . .
A grandmother prepared bowls of fruit for her family. The only fruits available . . .
On average there are 100,000 strands of hair on a person's head. Hair grows . . .
Gerry won 30% of the first 40% of the annual Discus Throw competitions. What . . .
Six students travel in a car. How many different ways can they take seats if . . .
Crazy Logic. Choose a number.
What is half of work and one third of gentleman?
If you take one third of GOOGLE and two thirds of ATT, what do you get?
What is missing?
Three parrots yell at Gerry every 5, 7 and 9 seconds, respectively. If they . . .
I can cut off 4 circles from a circular sheet of dough. I use the left-overs . . .
There are two gods named Orbis and Fidelis, one on your left, the other on your . . .
Divide the analog watch face with five straight parallel lines so that the sums . . .
Leslie Green asks: I am allergic to washing powder, but I don’t want my . . .
Leslie Green tells a story and asks : It has been several years since the . . .
Leslie Green asks: quot;The more debt you get into, the more credit card . . .
Leslie Green asks
A phrase you will hear on the news or from people . . .
The chocolate biscuit factory you are now in charge of has a problem. There are . . .
Leslie Green asks: Peter changes his old fashioned single 100W incandescent . . .
Forty-eight liters of water are poured into an aquarium of dimensions 50cm . . .
You are pitching your new idea to a panel of Venture Capitalists (VCs) to . . .
There are only two handshakes in a meeting: John shakes hands with a person, . . .
What is the main difference between the pictures on the left page and on the . . .
John works 4-hour shifts at a call center. He earns $4 per hour and $4 per . . .
Tom is choosing between two brands of AA batteries for his pocket flashlight. A . . .
A taxi company charges $1.75 for the first kilometer and 25 cents for each . . .
If 9 workers can build 9 houses in 9 months, then how many months would it . . .
Jim sells 80 percent of pineapples he had and throws away 10 percent of the . . .
If eight deciliters of Swiss apple juice, priced at $4.00 per liter, are . . .
A space rocket has a critical fuel-control system protected by 4 fuel . . .
A carnival game offers you the opportunity to bet $1 on a number from 1 through . . .
Jane wants to buy a car. The fuel efficiency is two times more important to . . .
9 farmers grow 9 apples trees in 9 years. How many years would it take for . . .
A bicyclist pedals downhill at 20 km/h (kilometers per hour) and uphill at 10 . . .
You have eight dimes; seven are real and one is fake. All the real ones weigh . . .
A city hall floor is to be tiled in the following pattern. The hall measures . . .
It costs $24 to paint a cube, the cost being proportional to the surface area. . . .
The traveling salesman problem: a salesman has to visit 9 towns and return . . .
The Chinese postman problem: a postman wants to travel along each road in his . . .
The diagram illustrates five villages, A, B, C, D, and E, with the distances . . .
The Legend of Carthage: Queen Dido and her followers arrived in North Africa. . . .
Anna can complete a project in 40 days. Bill can complete the project in 50 . . .
Choose the best advice for a strategic decision to the top management of a . . .
You have 240 golden bricks identical in size and appearance but one is lighter . . .
I am selling my car. People come to my garage one at a time and make bids to . . .
A goldfish needs 1000 cubic inches of water to live in. An aquarium is 20 . . .
John's dad pays him $2 for each correct answer he gives in his math homework . . .
Bob will work 5 days. Which payment plan should he choose?
"Letter frequency. Accurate average letter frequencies can only be gleaned by . . .
I gave $120 to Brett, Cindy, and Daniel. Together Brett and Cindy received . . .
The diagram shows a road network. All cars drive in one direction from A to F. . . .
The Lucas problem. François Édouard Anatole Lucas (1842-1891) was a French . . .
A red-line subway train arrives at a station every 5 minutes and stays for 30 . . .
Four people arrive at a river at night. There is a narrow bridge, but it can . . .
Every year, a man who had a million dollars at the beginning gives away half of . . .
The speed of a bus is 25 miles per hour (mph) including stops and 40 mph . . .
Job interview logic puzzle in a bank. Which of these pieces of information . . .
Wikipedia says that the equator is about 40,075 kilometers (24,901 miles) long; . . .
In a game, Anna and Bill take 1, 2, or 3 coins on each turn. The player to . . .
John and Mary have square tiles with sizes 2 cm by 2 cm, 4 cm by 4 cm, 6 cm by . . .
John and Mary have square tiles with sizes 5 cm by 5 cm, 10 cm by 10 cm, and 15 . . .
The size of a swimming pool is 25 x 12.5 meters. How many people must jump . . .
Which point cuts the rope into two equal parts?
If John walks up an escalator at a rate of one step per second, 12 steps take . . .
Two proofreading programs, A and B, discovered 30 and 40 errors, respectively. . . .
Anna was planning to buy 10 souvenirs from the honesty shop. She wanted some . . .
Water is pumped into an empty swimming pool at a linearly increasing rate, . . .
Twenty theater tickets for the first row were randomly distributed among 20 . . .
Two years ago, I bought a cottage for $800,000. I was short of money and . . .
Mrs. Brown bought 98 boxes of strawberries at $9 per box but 25 % of them were . . .
When I put 10 cubes of ice into my glass and they melt, the water doubles its . . .
Estimate how many symbols you can write on your body if one symbol requires one . . .
A father has left 47 donkeys for you to distribute to his three sons; 1/2 . . .
Mary and John manage two different projects and they have a common budget. . . .
Management support accelerates the execution of a project by 10% during the . . .
There are 190 people in a company including the project managers and CEO. . . .
One by one, 40 cars enter a company parking lot with 40 assigned places. The . . .
You pay $6 to enter a game. You roll 2 dice. You then have two choices: you . . .
I see the reflection of the mountain peak 10 meters from me. I know that the . . .
An entrepreneur sells 1,250 tickets for a show, with 20% of them sold with 20% . . .
A pirate boat is floating on a lake. The pirates throw a heavy chest with gold . . .
A space rocket with 4 engines blew off one of them after one-month of flight. . . .
What is the minimum monthly salary you negotiate with your boss if you need . . .
What is the total surface area of 100 identical cubes which together have a . . .
You have a large supply of 5kg and 12kg weights. Six 5kg weights and one 12kg . . .
Gerry plans to swim a total of at least 1000 laps in January. He swims every . . .
Texas experiences wide temperature fluctuations within a single day. On . . .
James bought a new car for $30,000. Each year it depreciates (loses value) at . . .
While eating out Gerry and Jim together tipped their server $7 in total. . . .
The water from an open swimming pool evaporates at a rate of 5 gallons per hour . . .
The limousine service makes 100 trips Center-Aeroport every day, each of which . . .
I decided to use a password that includes 4 different numbers, with each number . . .
Gerry drives from his home to Jane's house at 50 mph. How fast must he make . . .
Gerry gave half of his money to Jane. Next day, she gave half of all her . . .
A district sends, on average, a total of 205 million gallons of water each . . .
The manager of a company planned to distribute a $101 bonus to each employee . . .
If you have a piece of paper that is 0.1mm = 0.01cm thick, how many times will . . .
What is missing?
There are 17 parallels and 12 meridians on a globe. Into how many areas is the . . .
When Pinocchio lies, his nose gets twice as long. When he tells the truth, his . . .
What is average diameter of the logs if the height of the pile is 5.33m?
The diagram shows some of the results of a six-person contest. There are two . . .
I add blue blocks one by one on the top. Does the structure fail?
A worker prepared a block for a pyramid in a day. If every day the number of . . .
A girl walked along a level road and up a hill from home and back. Her pace . . .
Eugenia wants to make a simple bridge for her dog. Currently he has to run . . .
Now that I have made a vast fortune from my patented premium dog biscuits, I . . .
There are 10 coins and 5 of them are fake. The real gold coins have the same . . .
A train runs from Lausanne to Zurich at 100 km/hour without any stops and . . .
Shops have sales all the time to attract your business. Let the buyer beware! . . .
Leslie Green asks: My neighbor John has invented a perpetual motion machine. . . .
Leslie Green asks quot;Suppose a particular nuclear waste material has a . . .
Jane and Gerry compete in a best-of-five match. If Gerry plays so that his . . .
There is a fault with the cruise control on Hank's car such that the speed . . .
Before his death, a rich man signed his will. quot;If my wife gives birth to . . .
Gerry promises to be at Jane's house at 19:00. If he bikes at 15mph, he . . .
The train driver knows there is a Granny on board so he wants to give her a . . .
You may have heard the expression quot;The shortest distance between two points . . .
If $1,000 is invested in an account at 10% annual interest, how long will it . . .
Leslie Green asks: Electrical energy can be measured in Joules, but for . . .
Leslie Green asks: Suppose the light bulb in your fridge uses 1 Watt when on . . .
Leslie Green asks: quot;A professional design standard requires that free . . .
A taxi driver called John has 6-week annual holidays. If the average fare is . . .
A peasant bought a cow and a horse. Next day, he sold them for $1,800 each, . . .
A 1-liter bottle contains a mixture that is 1/4 antifreeze, 3/4 water. A . . .
Edgar chooses one of the double sheets of "The Daily Dog News". The two . . .
Use each digit, 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, exactly once to form two . . .
The first person is 100 cm tall. Each subsequent person is 20% taller than the . . .
The last digit of the number 777 is 
Find the hundreds digit (third digit from the right) of the product: 44444 x . . .
Which gives the largest answer?
Which gives the largest answer?
Make two fractions with all the digits from 0 to 9. Use each digit once. They . . .
What is 2 to the power of 16?
If you wrote all the whole numbers from 1 through 1000, how many times would . . .
With a 1 after a nine-digit number, it is the same as a 1 before it. Find . . .
I multiply the two page numbers and get 6162. What is the right-hand page . . .
If XY = 1024 and both numbers are integers, which of the following . . .
0.999 . . . means infinitely repeating decimals. What is the largest result?
A magic square is an arrangement of integers, in a square grid, where the . . .
Leslie Green asks: What is the next number in the sequence? 0, 3, 1, 4, . . .
Shakuntala Devi was undoubtedly the most brilliant arithmetic mental calculator . . .
Choose the condition when the inequality (2 + n)n > (1 + n)n is always true.
Line AB has the equation y = 0.5x + 3 Line CD is parallel to line AB. . . .
Which equation describes a line of symmetry for the shape?
Find the center of the prism with the following vertices. A(1,1,1), . . .
Which of the following graphs represents all values of x, such that: 
How many digits are in the result of the expression? 100111 
Which of the following gives the biggest answer?
If y is the fraction of the white area of the square, which graph shows the y . . .
How many integer values of x are the solutions of these two inequalities?
Find the point of intersection of these two lines.
Which equation represents the axis of symmetry of the graph of the parabola?
Three points of four are on a line. Which point is not on the line?
Xia and Yvonne collect buttons. Xia only collects the ones with two holes and . . .
Ten teams enter a basketball tournament. Each team plays one match against . . .
How many points of intersection do these three rays have? 
A square game board begins with a dark square alternating with light squares. . . .
Which function gives the angle in degrees between the hour and the minute hands . . .
Find Y.
Estimate the ratio of the large rectangle width to height if the two rectangles . . .
How many solutions are there for X?
A swimming pool is 12.5 x 8 x 3 meters. The average volume of a human body is . . .
A tree increases its number of nuts at the rate of 100% every year. What was . . .
What amount of water should be added to reduce 200 milliliters of 5 percent fat . . .
A car starts traveling at an initial speed of 120 km per hour (kmph), the . . .
What are the smallest and largest integers that will make this expression true? 
Evguenia walked to school. Twelve minutes after she left, Sasha started. His . . .
There are 190 coconuts in a basket. Sailors one after another take out half of . . .
The weights of each pair of these boxes are 98kg, 101kg, and 102kg. What is . . .
Mike’s age, M, is equal to the sum of the ages of his four children. His age N . . .
Two trains, each 400 meters long, pass each other completely in 10 seconds when . . .
Two tourists paddled downstream for 2 hours and then upstream for 4 hours. . . .
The Smith family consists of parents, children, and animals. Some of them are . . .
In a city, sixty percent of the men are married to eighty percent of the women. . . .
How many "yes or no" questions are needed to guess any 5-digit code?
In a recent election, 1111 people voted for two parties. If the ratio of the . . .
Find x.
Divine the value of the Divine proportion AC.
The balance is in equilibrium. Find Z.
If 3 pens and 5 pencils cost as much as 5 pens and 2 pencils, by how much is a . . .
Gerry and Jane are exactly 100 km apart. Gerry leaves his place running at 10 . . .
The occupancy percentage of a hotel is 64% for the four summer months and 46% . . .
Water increases its volume by 1/11 when freezing. By what part of its volume . . .
Leslie Green asks: Given Cartesian axes of infinite extent, find the ratio . . .
Find the ratio of the areas above and below the parabola y = . . .
A grocery store sells Brazilian cacao in 15-kg bags and Ecuadorian cacao in . . .
A cube is painted on the outside and then divided into one-unit cubes. The . . .
There are 1000 students in a high school. 20% of girls and 30% of boys were . . .
A fence around a rectangular garden has a perimeter of 14 meters. Its length . . .
Tim travels 15 meters north of the flag in the football stadium. He turns . . .
S varies directly as the square of (H+1) S = 121 when H = 10 Find H when S = . . .
A wire is wound around a circular rod. The wire goes exactly 5 times around . . .
Which is the best estimate of the area of the colored shape?
These two shapes are similar. What is the length of x?
Identify the area of the rounded square.
A boy stacked colored cubes in a square pyramid like the one shown here. The . . .
A six-pointed regular star consists of two areas. What is the ratio of the . . .
The figure shows a red equilateral triangle inscribed within another . . .
If the volume of a cube is X cubic meters and the total surface area of the . . .
The side of the colored square is x cm. What is the area of the red . . .
The three circles have fixed centers, and the diameter of a circle is 10% less . . .
L3 and L4 are two parallel lines in a plane. If L3 has 3 points equally . . .
What is the total number of lines of tangency that are common to circle C1 and . . .
For this rectangular-faced solid (cuboid), which plane(s) contain(s) B and . . .
Two similar pyramids have volumes of 216 m3 and 64 m3. . . .
AB is parallel to CD. What is the value of X?
There are 2 identical circles. Circle A remains fixed, while Circle B makes 1 . . .
G is the area of the green region inside the biggest circle. R is the total . . .
The area of the external triangle is equal to 1. Its sides' midpoints are . . .
The pattern of shading in one quarter of a square is shown in the diagram. . . .
What is the maximum number of squares you can make using twelve identical . . .
A gardener has to reach the island in the middle of a pond without getting wet. . . .
Three reservoirs have the same height h=1. Which reservoir is bigger?
What is the largest semi-circle that can be inscribed in a square with a side . . .
Twenty matchsticks form five squares (one 3x3 and four 1x1). How many . . .
A ladder leans against a vertical wall. The top of the ladder is 4m above the . . .
If the length of the hour and minute hand of a clock are 3cm and 6cm . . .
All inner lines connect the corners of the big square and the midpoints of the . . .
A square is inscribed in a right triangle. Find the greatest possible ratio . . .
What value of X gives the greatest ratio of red area to the area of the big . . .
Among the following shapes of equal area, which has the smallest perimeter? 
The sizes of the sealed bottle with water are shown in the figure. Find the . . .
How many equilateral triangles can you make using six identical line segments? 
The following pattern is cut and folded to a square-based pyramid. What size . . .
John is using the spinner shown here to define the movement. Blue means one . . .
How much wrapping paper is needed to entirely cover a box that is 40 cm by 30 . . .
What is the ratio of the green area to the red area?
Four squares have dimensions as indicated in the picture. What is the area . . .
What is the maximum number of possible points of intersection of N different . . .
The diameter of one hair is 0.2 mm. Estimate the diameter of a plait of 1000 . . .
Two lines trisect (divide into three equal parts) each side of the polygon . . .
The shaded rhombus is formed by joining vertices of the square to the midpoints . . .
The diagram shows 15 billiard balls that fit exactly inside a triangular rack. . . .
The picture shows the areas of three rectangles. What is the area of the . . .
Two triangles form seven separate regions. What is the greatest number of . . .
There are six ways to travel from point S to point F on a small cube if only . . .
Estimate the area of the smallest square that can enclose the regular hexagon . . .
A, B, and C are squares with sides of length 1; D, E, and F are isosceles . . .
I drew three lines from the center of a square that has sides with a length of . . .
What is the maximum number of pieces that an apple can be divided into with . . .
Each of these five circles is tangent to at least 3 others. The medium sized . . .
Find the radius of the circle.
In a city, there were seven bridges. There was a tradition that a newly . . .
A sphere fits inside a cube. The maximum possible ratio of the volume of the . . .
I want to cut a wooden cube that is five inches on each side into 125 one-inch . . .
What line divides the green polygon into two parts of equal area?
I need 1 + 4 + 9 + 16 + 25 = 55 cubes to build a pyramid with a height of 5 . . .
What is the volume of the second glass compared to the first one?
The Babylonians used a base 60 number system. What shape inspired them to . . .
Connect N points on the circumference of a circle. What is the largest number . . .
I take a map of the city where I live and lay it on my table. There is a . . .
What is the largest number of intersections of N lines?
I connected the midpoints of a polygon and constructed a new polygon that was a . . .
A pyramid and a tetrahedron with edges of the same length are glued together on . . .
I need 1 + 9 + 25 = 35 cubes to build a pyramid with a height of 3 cubes. . . .
Inspired by Boris Kordemsky. Four Knights problem: Cut the chessboard into . . .
How many 1x1 squares fit into the large square with the side length 4.8? . . .
What is the greatest possible number of points of intersection for 11 lines in . . .
The picture shows three squares with the side lengths of 10, 8, and 4 cm. What . . .
A trapezoid is formed by cutting off the top part of an isosceles right . . .
If regular stars are placed as shown to form a complete circle, how many stars . . .
What fraction of this regular octagon is shaded?
The stripes have the same width. What part of the square is red?
A circle goes through two adjacent vertices of a square and it is tangent to . . .
The figure shows adjacent squares. Find the sum of angles X and Y.
What is the probability of breaking a stick into three pieces and forming a . . .
A rectangular yard with an area of 24 m2 has sides in the ratio 2:3. . . .
Which triangle has the greatest area?
Which is a better fit? The smaller the percentage of the ‘area left over,’ . . .
Two perpendicular lines form four segments with lengths a, b, c, and d. . . .
How many pentagons are there?
The golden border of the hexagonal brooch with maximum size 60 mm includes a . . .
What is the maximum number of sections into which a pancake may be divided by . . .
The numbers show the areas of corresponding triangles. What is the area of . . .
What is the perimeter of a right triangle whose shorter sides are 9 and 12 . . .
The picture shows a large cube 4 x 4 x 4 that was assembled from one-unit . . .
What is the largest number of straight lines you can draw through 9 points, so . . .
John cuts a large piece of cheese into small pieces using straight cuts from a . . .
Gerry has 24 meters of fence and wants to make a rectangular garden with the . . .
Take two sheets of A4 paper (210 x 297 millimeters or 8.3 x 11.7 inch). Roll . . .
Estimate the maximum number of smaller 1-inch circles that fit in a larger . . .
There are two paths in a rectangular garden. Find the length of the shorter . . .
Which shape has the smallest perimeter?
What is the largest distance if the angle B is right?
Three semicircles are constructed on the hypotenuse and legs of a right angle . . .
There are 3 circles of equal diameter. A line is tangent to the third circle, . . .
If the area of the left triangle is 100%, what is the area of the second . . .
John has an average of 89 on his three math exams. To earn an A, he must have . . .
I roll two dice. What is the probability that the second number is greater . . .
How many different 7-digit phone numbers can be used by a phone company? The . . .
The table shows the results of a competition among 5 teams. Each team plays . . .
As each of five eggs is weighed, the average weight increases by one gram each . . .
The probability that two randomly chosen people in a big city are younger than . . .
In a game, you have a 1/5 probability of winning $100 and 4/5 probability of . . .
What is the average of these numbers?
John is sick 6 days per year. The probability of being sick on a Saturday or a . . .
This formula, developed by Austrian mathematician Richard Von Mises, shows the . . .
Five people sit at a round table. What is the probability that they sit in . . .
What is the units digit of 1! + 2! + 3! + ... + 2011!? 4! means 1 x 2 x 3 x 4
Abbey has a dog Abby. She places 5 tiles with the letters of her surname into . . .
Two princes and two princesses are ready to marry. Everybody independently . . .
I randomly place three crosses into different cells of the grid. What is the . . .
A 4-character password uses exactly two different digits. Each digit can be 0, . . .
After a rodeo, four cowboys have a meeting in a saloon. Each cowboy has only . . .
Make 727 by using three 7s. You can use any math operator that you would . . .
A venture capitalist has choosen to invest in only one of three start-up . . .
How many different cubes can I make by using six different colors such that . . .
In a venture investment fund, all investors continue to invest into a new . . .
Logic puzzle: Counting down from 100 by one, which number comes next?
What is the probability that two dominoes drawn randomly from a standard set . . .
This picture shows the first five rows of Pascal's triangle. What is the sum . . .
What is heavier than a cumulus cloud, which is about 1 cubic kilometer in . . .
Eight bugs are at the eight corners of an equilateral cube. Each bug randomly . . .
Logic question. What is the easiest way to make the following equation . . .
A chess queen attacks all squares along its path horizontally, vertically and . . .
We want to merge 4 companies into one large company. How many ways are there . . .
Find the sum of the series: 1/3 + 1/9 + 1/27 + 1/81 + . . . 
Place the cards into two boxes so that the probability of randomly drawing a . . .
Alex possesses 52% of a business and the rest belongs to Bill. They take . . .
Find the infinite sum: 1 - 1 + 1 - 1 + 1 - 1 + 1 - 1 + 1 - 1 + . . . 
A player must match three different numbers chosen from the integers 1 to 30 . . .
The picture shows a subway map. If it takes 3 minutes to go from one station . . .
In a country, a baby is born every 5 seconds, a person dies every 45 seconds, . . .
Anna and Bill roll a six-sided die. The first person to roll a six wins. Anna . . .
You can throw as many darts as necessary at the board shown in the picture. . . .
John threw 8 fair dimes and Mary 9 dimes. What is the probability that Mary . . .
Five students Anna, Bill, Craig, Daniel, and Eugene commute by bus. Every . . .
If the probability of observing a white car in 10 minutes on a motorway is . . .
How many squares are there on a chess board?
My car can travel 20 km on one liter of gas on the motorway and 12 km on one . . .
When 4 coins are tossed, what is the probability that exactly 2 are heads?
Veryfast Airlines loses 20% of the luggage. Gerry puts his three favorite toys . . .
95.8% of James' classmates have different numbers of hairs than he has. How . . .
A ball rebounds half of the height from which it is dropped in a sport hall. . . .
When Jane plays against Gerry in her favorite game, the odds are 5 to 3 that . . .
Steve wonders "Why don’t I have a girlfriend?" He uses the following . . .
The cost of living increased in the first year and it decreased in the second . . .
How many ways can five runners take first, second, and third place in a . . .
I bought a 20'' (the diagonal size) laptop with the ratio of the screen width . . .
I throw a coin on a chessboard. The diameter of the coin is a half of the side . . .
Gerry's favorite digit is 7. What is the probability that there is at least . . .
I put red and white chocolate candies into a bag. I randomly took 2 candies, . . .
Coin landing on its edge I flip a fair Swiss franc* and it falls in . . .
I roll two dice, one with the left hand and one with the right. If the left . . .
Jane was a naughty little girl. When she used to play 2-dice games with her . . .
Martin has ten thousand dollars in the Mad Money's bank account. The interest . . .
Einstein, the hyper-intelligent house cat, is busy walking from one corner of a . . .
Martin, the mathematical mole, has dug an extensive network of underground . . .
Marek, the pan-dimensional super being, has arbitrarily defined his current . . .
Twenty Knights sit around the Round Table in the following order: 1. King . . .
Leslie Green asks: quot; The sinusoidal waveform shown has a peak amplitude of . . .
Christmas is getting near, and a four person company wants to run a Secret . . .
What are the odds of getting at least two tails in a row if you flip a dime . . .
Evguenia's teacher assigns 24 math problems to solve. She sorts them from the . . .
The twins are the same height. They place four identical blocks as shown in . . .
Ten years ago, Bob was three times as old as Anna. Today, he is twice as old . . .
Statement 1: There are 3 animals in a room. Statement 2: All of the animals in . . .
How many straight lines are needed to separate each star from all the others?
Two gears, one with 11 teeth and the other one with 18 teeth, have teeth marked . . .
You take half of the syrup and mix it with the water, and then take the same . . .
A hunter met two shepherds, one of whom had three loaves of bread and the . . .
In-Out Machine transforms 111121 into 100. The same machine transforms 121244 . . .
An analog clock loses 15 minutes each hour. If the clock is set correctly at . . .
The product of 2 integers is 1000. Find the smallest possible sum of these . . .
The addition shown here has 21 terms and the last element consists of 21 9's. . . .
I put $990 into 10 envelopes. I try to compose all possible whole amounts . . .
If 12 workers take 7 hours to build a brick wall 21 m long and 4 m high, how . . .
Alex has bills of different dollar values. There are five times as many ones . . .
Four painters can complete a painting job in 20 days. 12 more painters join . . .
Anna bought 1 slice of mushroom pizza and 2 slices of cheese pizza for a total . . .
Which of these diagrams could be drawn without taking the pen off the page and . . .
Each of these seven cells contains one number from 1 to 7, using all seven . . .
You have four piles: three piles with real coins and one pile with fake coins. . . .
A bee crawls along the sides of the honeycomb hexagons. It has moved from . . .
On a 5 × 5 grid, I place a 1x2 card so that it exactly covers two squares. I . . .
A project manager has to determine whether to purchase or rent four cars for a . . .
I want to measure exactly six minutes from the moment I touch an hourglass, . . .
One hundred soldiers form a 10 x 10 square. From every column, the tallest . . .
A donkey must transport 900 carrots to the market, which is 300 miles away. . . .
I arrange five marbles randomly in a ring. There are two green and three . . .
You have a part of a black-and-white map of a reef coast. You are at point A . . .
In any 24-hour period, how many times are the digits of a 24-hour digital clock . . .
Alex greeted Bill. Bill greeted Cindy. Alex did not greet Cindy. If the . . .
Kevin cleans rooms in a student hostel; he earns twice as much for cleaning a . . .
Divide the circles into two disjoint groups so that the sums of the numbers in . . .
Bob earns $48,000 per year and has two weeks of paid vacation. He works five . . .
Thinking outside the box: Which statement is correct?
Thinking outside the box. Solve this:
Which symbol goes next?
The rear tires of a car wear out after 40,000 miles, while the front tires wear . . .
There are 123 part-time employees and 321 full-time employees in a company. . . .
Mary can complete an activity in 40 days. John can complete the activity in 50 . . .
Find the logic: 12345678 rarr; 4 234567 rarr; 2 . . .
A 44-month long project is divided into three consecutive activities. The . . .
"This is a capital letter of the alphabet that's been folded just once. Which . . .
Two trains are 1 kilometer apart on a single track railway line. They set off . . .
Two successive increases of 25% and 25% are followed by two successive . . .
If Gerry gives Jane one apple, they will have the same number of apples. If . . .
At the end of each week, Gerry forgot 50% of what he knew the week before. At . . .
After an hour, Evguenia catches and frees 10 fish. If there are 100 fish in a . . .
Guess!
What is the word coiled inside this circle?
A grandmother prepared bowls of fruit for her family. The only fruits available . . .
On average there are 100,000 strands of hair on a person's head. Hair grows . . .
Gerry won 30% of the first 40% of the annual Discus Throw competitions. What . . .
Crazy Logic. Choose a number.
What is missing?
Three parrots yell at Gerry every 5, 7 and 9 seconds, respectively. If they . . .
I can cut off 4 circles from a circular sheet of dough. I use the left-overs . . .
There are two gods named Orbis and Fidelis, one on your left, the other on your . . .
Divide the analog watch face with five straight parallel lines so that the sums . . .
Leslie Green asks: I am allergic to washing powder, but I don’t want my . . .
Leslie Green asks: quot;The more debt you get into, the more credit card . . .
The chocolate biscuit factory you are now in charge of has a problem. There are . . .
Leslie Green asks: Peter changes his old fashioned single 100W incandescent . . .
Forty-eight liters of water are poured into an aquarium of dimensions 50cm . . .
You are pitching your new idea to a panel of Venture Capitalists (VCs) to . . .
There are only two handshakes in a meeting: John shakes hands with a person, . . .
What is the main difference between the pictures on the left page and on the . . .
Tom is choosing between two brands of AA batteries for his pocket flashlight. A . . .
A taxi company charges $1.75 for the first kilometer and 25 cents for each . . .
If 9 workers can build 9 houses in 9 months, then how many months would it . . .
Jim sells 80 percent of pineapples he had and throws away 10 percent of the . . .
A space rocket has a critical fuel-control system protected by 4 fuel . . .
Jane wants to buy a car. The fuel efficiency is two times more important to . . .
A bicyclist pedals downhill at 20 km/h (kilometers per hour) and uphill at 10 . . .
A city hall floor is to be tiled in the following pattern. The hall measures . . .
It costs $24 to paint a cube, the cost being proportional to the surface area. . . .
The traveling salesman problem: a salesman has to visit 9 towns and return . . .
The Chinese postman problem: a postman wants to travel along each road in his . . .
The diagram illustrates five villages, A, B, C, D, and E, with the distances . . .
You have 240 golden bricks identical in size and appearance but one is lighter . . .
A goldfish needs 1000 cubic inches of water to live in. An aquarium is 20 . . .
"Letter frequency. Accurate average letter frequencies can only be gleaned by . . .
I gave $120 to Brett, Cindy, and Daniel. Together Brett and Cindy received . . .
The diagram shows a road network. All cars drive in one direction from A to F. . . .
The Lucas problem. François Édouard Anatole Lucas (1842-1891) was a French . . .
A red-line subway train arrives at a station every 5 minutes and stays for 30 . . .
Four people arrive at a river at night. There is a narrow bridge, but it can . . .
Every year, a man who had a million dollars at the beginning gives away half of . . .
Wikipedia says that the equator is about 40,075 kilometers (24,901 miles) long; . . .
Which point cuts the rope into two equal parts?
If John walks up an escalator at a rate of one step per second, 12 steps take . . .
Anna was planning to buy 10 souvenirs from the honesty shop. She wanted some . . .
Twenty theater tickets for the first row were randomly distributed among 20 . . .
Mrs. Brown bought 98 boxes of strawberries at $9 per box but 25 % of them were . . .
Estimate how many symbols you can write on your body if one symbol requires one . . .
One by one, 40 cars enter a company parking lot with 40 assigned places. The . . .
An entrepreneur sells 1,250 tickets for a show, with 20% of them sold with 20% . . .
A pirate boat is floating on a lake. The pirates throw a heavy chest with gold . . .
What is the total surface area of 100 identical cubes which together have a . . .
You have a large supply of 5kg and 12kg weights. Six 5kg weights and one 12kg . . .
Texas experiences wide temperature fluctuations within a single day. On . . .
While eating out Gerry and Jim together tipped their server $7 in total. . . .
I decided to use a password that includes 4 different numbers, with each number . . .
A district sends, on average, a total of 205 million gallons of water each . . .
If you have a piece of paper that is 0.1mm = 0.01cm thick, how many times will . . .
What is missing?
There are 17 parallels and 12 meridians on a globe. Into how many areas is the . . .
When Pinocchio lies, his nose gets twice as long. When he tells the truth, his . . .
What is average diameter of the logs if the height of the pile is 5.33m?
The diagram shows some of the results of a six-person contest. There are two . . .
I add blue blocks one by one on the top. Does the structure fail? 
A worker prepared a block for a pyramid in a day. If every day the number of . . .
Eugenia wants to make a simple bridge for her dog. Currently he has to run . . .
Now that I have made a vast fortune from my patented premium dog biscuits, I . . .
Shops have sales all the time to attract your business. Let the buyer beware! . . .
Leslie Green asks: My neighbor John has invented a perpetual motion machine. . . .
Leslie Green asks quot;Suppose a particular nuclear waste material has a . . .
Jane and Gerry compete in a best-of-five match. If Gerry plays so that his . . .
The train driver knows there is a Granny on board so he wants to give her a . . .
You may have heard the expression quot;The shortest distance between two points . . .
Leslie Green asks: Electrical energy can be measured in Joules, but for . . .
Leslie Green asks: Suppose the light bulb in your fridge uses 1 Watt when on . . .
Leslie Green asks: quot;A professional design standard requires that free . . .
A peasant bought a cow and a horse. Next day, he sold them for $1,800 each, . . .
A 1-liter bottle contains a mixture that is 1/4 antifreeze, 3/4 water. A . . .
Edgar chooses one of the double sheets of "The Daily Dog News". The two . . .