Three tiny motor boats set out from the shore of a lake, each with a full fuel tank and 3 full fuel cans. Each fuel can stores the same amount of fuel as held in the onboard tank. The three boats are tied together until it is time for one or more to separate. The boats use fuel at a steady rate, regardless of the amount of fuel on board. One tank of fuel lasts for 1 hour.

Each boat can only hold 3 full fuel cans, and a fuel can, once opened, has to be completely emptied into the fuel tank of the boat it is on. Fuel in the onboard tanks cannot be shared.

If fuel cans are optimally transferred, what is the maximum time one boat can continue on its journey?

Author: Leslie Green