A man’s car runs out of gas on the highway, and he walks to the nearest town. He goes to a gas station, and realizes he needs exactly 6 gallons of gas. Any less and he won’t make it to town, and he doesn’t have the money for any more. He has two unmarked bottles, one holding 13 gallons and one holding 9. How does he get exactly six gallons?
Assume that it’s a serve-yourself pump and no one is around to help.
Answer
He fills up either can until the gas register reads exactly six gallons.
