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 and pour water from the 3 gal jug into the empty 5 gal jug. Do this again and stop once the 5gal jug is full, leaving 1gal in the 3gal jug. Empty the water from the 5 gal jug and pour the 1gal from the 3gal jug into the 5gal jug. Then, fill and pour the 3gal jug into the 5gal jug again, resulting in exactly 4 gallons.

Posted by randy on 2002-11-02 09:55:06