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).

Let us denote the 3 gallon jug by A and the 5 gallon jug by B.

Step 1: Fill B with water.

Step 2: Empty B into A. Precisely  2 gallons now remain in B.

Step 3: Empty jug A.

Step 4: Pour the 2 gallons from B into A.

Step 5: Fill out B. Transfer 1 gallons of B into A.

B will now contain precisely (5-1) =  4 gallons.

Thus, we have measured out exactly 4 gallons of water  as desired.

Edited on April 10, 2023, 12:48 am

Posted by K Sengupta on 2007-06-18 05:49:43