C.5 Volume ratio of alcohol

There are two beakers A and B, 10L alcohol is in A and 10L water is in B. 

At first, I take 5L out of A and put it in B and stirred it well. 

Next I take 5L out of B and put it in A. 

Indicate the volume of the alcohol in A and B by the ratio of the least integer.






Answer
2 : 1

Solution
5L comes into B from A and the volume of B is to be 10 + 5 = 15L.

The ratio of alcohol of B is 5 / (10+5) = 1/3. 

The volume of alcohol in 5L out of B is 5L × (1/3) = 5/3L. 

The volume of alcohol of A becomes 5 + 5/3 = 20/3L. 

The volume of alcohol left in B is 5 - 5/3 = 10/3L. 

The ratio of the volume of alcohol in A and B is 20/3 : 10/3 = 2 : 1.