A vessel contains 20 litres containing milk and water in the ratio 3 : 2. Ten litres of this milk is removed and replaced with equal amount of pure milk. If this process is repeated once again, find the final ratio of milk and water.

vessel contains 20 l in the ratio milk and water of 3: 2

so

3x +2x = 20l

x = 4 l

so ,milk = 12l

      water = 8 l

ATQ

Ten litres of this milk is removed and replaced with equal amount of pure milk

when we removed anything the ratio remains same 

so milk and water ratio is 3: 2 only

 now vessel contains 10 l in the ratio milk and water of 3: 2

3x +2x = 10l

x = 2 l

so ,milk = 6l

water = 4 l

and 10 l pure milk is added so milk = 16 l and water = 4 l 

ratio = 4 : 1

this process is repeated once again that is ,Ten litres of this milk is removed and replaced with equal amount of pure milk

so milk and water ratio is 4 : 1 only

now vessel contains 10 l in the ratio milk and water of 4 : 1

4x +x = 10l

x = 2 l

so ,milk = 8l

water =  2l

and 10 l pure milk is added so milk = 18 l and water = 2 l

ratio = 9 : 1