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.)

1. Fill the 6.
2. Dump the 6 gallons into the 11
3. Fill the 6 again.
4. Dump all that can fit into the 11. You now have 1 gallon in the 6.
5. Put that one gallon into the tank.
6. Fill the 6 with the 11. You now have 5 gallons in the 11.
7. Empty the 6 into the tank.
8. Empty the 11 into the 6.
9. Top the 6 off with one gallon.
10. Empty the last 6 gallons into the tank.

Posted by George on 2006-10-12 16:08:14