A mixture has milk and water in the ratio (by volume) of 8 : 3. If 3 litres of water is added to it, then new ratio of milk and water becomes 2 : 1. What are the quantities of milk and water respectively in the mixture initially?

24 litres and 9 litres

Initial Ratio,

 Milk : Water

  8    :    3

3 liters of water is added,

 Milk : Water

  2   :    1

⇒ Making ratio of Milk equal in both the solutions, we multiply final solution with 4.

⇒ (2 : 1) x 4 = 8 : 4

⇒ Difference in Initial water ratio and Final water ratio = (4 - 3) = 1 

⇒ 1 unit = 3 liters

⇒ The quantities of milk and water respectively in the mixture initially,

 Milk = 8 x 3 = 24 liters,   Water = 3 x 3 = 9 liters,