Correct Answer - Option 2 : 50 litres

**GIVEN :**

In a container contained 160 liters milk.

Few litres of milk is replaced by water then the quantity of milk will be 3 times the quantity of water.

**CONCEPT :**

Replacement of Mixture.

**CALCULATION :**

The quantity of milk is 160 litres

Few litres of milk replaced by water, then the quantity will be 3 times of the water

⇒ milk = 3 water

⇒ milk/water = 3/1

It means total quantity is (3 + 1) = 4 units

⇒ 4 units = 160 litres

⇒ 1 units = 40 litres

Then, Milk = 3 × 40

⇒ 120 litres

Water = 40 litres

According to the questions,

Again 20 litre of mixture withdraw

⇒ 160 – 20

⇒ 140 litres

Then quantity of milk and water ratio is same

⇒ 1 unit = 140/4

⇒ 1 unit = 35 litres

Milk = 3 × 35 = 105 litres and water = 35 litres

After added the water 15 litres, then quantity of water

⇒ 35 + 15

⇒ 50 litres

**∴ The quantity of water in final mixture is 50 litres.**