A mixture of milk and water measures $60$ litres and contains $20\%$ water. How many litres of water should be added so that water becomes $25\%$ of the final mixture?

Question

A mixture of milk and water measures $60$ litres and contains $20\%$ water. How many litres of water should be added so that water becomes $25\%$ of the final mixture?

Option A

2 litres

Option B — Correct answer

4 litres

Correct choice.

Option C

6 litres

Option D

8 litres

Explanation

Initial water $=12$ litres. If $x$ litres are added, then $\frac{12+x}{60+x}=\frac14$. Solving gives $x=4$.

Chapter Mock 10: Mixture and Alligation