Question

In 162 litres pure milk, 18 liters of milk is replaced by water and if this process is repeated one more time, then find the quantity of water in the final mixture
1. 128
2. 34
3. 43
4. 126
5.

Answer 1

Correct Answer - Option 2 : 34

Given:

Quantity of pure milk = 162 litres

18 litres of milk is replaced by water 2 times.

Formula used:

Suppose a container contains A units of a liquid from which B units are taken out and replaced by water.

After n operations, operations, operations, operations,

Quantity of pure liquid in the final mixture = A {1 - (B/A)}ⁿ

Calculation:

According to the question,

Quantity of pure milk in the final mixture = A {1 - (B/A)}ⁿ

⇒ 162 × {1 - (18/162)}²

⇒ 162 × {1 - (1/9)}²

⇒ 162 × (8/9)²

⇒ 162 × (64/81)

⇒ 128

Now, the quantity of water = 162 - 128 = 34

∴  The quantity of water in the final mixture is 34 litres.