Correct Answer - Option 2 : 18 : 19

Given:

The total amount of mixture is 108 litres.

The ratio of milk and water is 2 : 1

The amount of water is added is 40 litres.

**Concept Used:**

Total mixture = Quantity of milk + Quantity of water

Calculation:

Let the initial amount of water and milk be x, 2x.

Total amount of mixture = x + 2x = 3x

⇒ 3x =108

⇒ x = 108/3 = 36

Amount of water = 36 litres

Amount of milk = 2 × 36 = 72 litres

Then, 40 litres of water is added to the mixture

New amount of water = 36 + 40 = 76 litres

The new ratio of milk and water = 72 : 76 = 18 : 19

**∴The ratio of milk and water in final mixture is 18 : 19.**