A man's car runs out of gasoline. His car tank holds exactly 13 gallons. He has three empty unmarked containers which can hold 3 gallons, 6 gallons, and 11 gallons. Using only these containers at the gas station, how can the man bring back exactly 13 gallons?

(He is not allowed to buy over 13 gallons and dispose of the extra.)

usually problems like this are figured out so that it is actually possible to solve the problem using only the containers with the measurements specified, and the only actions you can do are fill each container all the way, either from it being empty, or from having some left over in it after filling another container.

generally, it is allowable to completely empty a container at any point in the problem, but this one specificlly states otherwise. that, to me, was an indication that there was a specific solution that could be attained without having to use more than 13 gallons.

after working on it for a while, i began to suspect that it was impossible, but i was looking forward to seeing a real solution. guess i'm just stuck being disappointed..
worse, the posted solutions are just links to people's guesses that break the rules of the problem.

so, my suspicions were correct, but..why bother making a specific problem like this without any idea how (or if) it can be done?

i don't get it... *sob*

Posted by DJ on 2003-04-20 14:45:07