Correct Answer - Option 1 : 60 litres
Given:
Total mixture = 60 litres
The ratio of milk and water = 2 ∶ 1
Calculation:
Let the quantity of milk in the mixture be 2x litres and quantity of water in the mixture is x litres
Total mixture = 2x + x = 3x = 60
⇒ x = 60/3 = 20
Milk in the mixture = 2x = 40 litres
Water in the mixture = x = 20 litres
Let the quantity of water added be y litres
After adding water the ratio of Milk ∶ Water = 1 ∶ 2
40 ∶ (20 + y) = 1 ∶ 2
⇒ 80 = 20 + y
⇒ y = 60 litres
∴ 60 liters of water should be added