Measure 4 gallon of water from 3 gallon and 5 gallon water jar

Problem :

How to measure exactly 4 gallon of water from 3 gallon and 5 gallon jars, Given, you have unlimited water supply from a running tap.


Solution:

Step 1. Fill 3 gallon jar with water. ( 5p – 0, 3p – 3)

Step 2. Pour all its water into 5 gallon jar. (5p – 3, 3p – 0)

Step 3. Fill 3 gallon jar again. ( 5p – 3, 3p – 3)

Step 4. Pour its water into 5 gallon jar untill it is full. Now you will have exactly 1 gallon water remaining in 3 gallon jar. (5p – 5, 3p – 1)

Step 5. Empty 5 gallon jar, pour 1 gallon water from 3 gallon jar into it. Now 5 gallon jar has exactly 1 gallon of water. (5p – 1, 3p – 0)

Step 6. Fill 3 gallon jar again and pour all its water into 5 gallon jar, thus 5 gallon jar will have exactly 4 gallon of water. (5p – 4, 3p – 0)

We are done !

Another way
- Fill 5 gallon jar.
- Pour all its water to 3 gallon jar, thus leaving exactly 2 gallon water in 5 gallon jar.
- Empty 3 gallon jar and pour all of 5 gallon jar water into it, thus now 3 gallon jar will have exactly 2 gallon of water.
- Fill 5 gallon jar again and pour its water to 3 gallon jar until that is full. So exactly 4 gallon water will remain in 5 gallon jar.