Math Puzzles and Games


8. A military car carrying an important letter must cross a desert. There is no petrol station on the desert and the car has space only for petrol that lasts to the middle of the desert. There are also other cars that can transfer their petrol into one another. How can the letter be delivered?

Solution: There are 4 cars needed, including the car with the important letter (which travels to the middle of the desert). Its empty tank must be filled to the top to get to the end of desert. The way between the military base (where the cars and petrol is) and the middle of the desert can be divided into 3 thirds. 3 cars will go in their thirds back and forth and over spilling 1/3 of their tanks. This way the tank of the important car will be filled and the letter will be delivered.