40 litres of a mixture have milk and water in the ratio 5 : 3. How much milk must be added to make the ratio 2 : 1?

Explanation

1. 01

   Milk 25 litres, water 15 litres.

2. 02

   Water stays at 15, so for 2 : 1 milk must be 30 litres: add 5 litres.