Question

A drum contains 40 litres of milk. One-fourth of the milk is taken out and replaced with water. Then, half of the mixture is taken out and replaced with water. What is the respective quantity of milk and water left in the drum?
1. 10 litres and 30 litres
2. 25 litres and 15 litres
3. 15 litres and 25 litres
4. 20 litres and 20 litres

Answer 1

Correct Answer - Option 3 : 15 litres and 25 litres

A drum contains 40 litres of milk.

One-fourth of the milk is taken out and replaced with water. 

One-fourth of the milk = 1/4 × 40 litres

One-fourth of the milk = 10 litres

Milk left in drum is = (40 - 10) = 30 litres 

And 10 litres of water was added.

Half of the mixture is taken out and replaced with water. 

Half of 30 litres milk = 1/2 × 30 = 15 litres

And 15 litres of water was added.

The respective quantity of:

Milk left in the drum = (30 - 15) = 15 litres

Water left in the drum = (10 + 15) = 25 litres

Hence, '15 litres and 25 litres’ is the correct answer.