A certain quantity of a mixture of milk and water are in the ratio of 3: 2 respectively.If 25 litres of mixture is taken out and replaced with 7 litres of water, then the ratio of milk and water becomes 1: 1. Find the initial quantity of mixture.
1
78 litres
2
90 litres
3
60 litres
4
72 litres
5
84 litres