In a 56 liters mixture of milk and water, the ratio of milk to water is 5 : 2. In order to make the ratio of milk to water 7 : 2, some quantity of milk is to be added to the mixture. The quantity of the milk present in the new mixture will be:

56 liters

Initial mixture,

 M  :  W

 5   :  2

After adding some milk, final solution,

  M  :  W

  7   :  2

⇒ Quantity of initial solution = 56 liters,

⇒ (5 + 2)units = 56,

⇒ 7 units = 56,

⇒ 1 unit = 8 liters,

⇒ Amount of  Milk present in new mixture = 7 x 8 = 56 liters.