You have a 5 gallon jug and a 3 gallon jug. You have no other measuring devices.

Measure out exactly 4 gallons of water (Assume you have a river handy, or some other limitless water supply).

Fill the 3 and pour it into the 5.
Refill the 3 and use that to fill the 5. You will have 1 gallon left in the 3 jug.
Dump the water in the five, and empty the 3 jug into the 5 jug.
Add another 3 gallons to the 1 gallon in the 5 jug, and then you have 4 gallons.

Posted by Lewis on 2003-05-04 20:38:57