A dishonest milkman sells milk at cost price but mixes water and gains $25\%$. The percentage of water in the mixture is:

Question

A dishonest milkman sells milk at cost price but mixes water and gains $25\%$. The percentage of water in the mixture is:

Option A

10%

Option B

15%

Option C — Correct answer

20%

Correct choice.

Option D

25%

Explanation

Let milk cost Re 1 per litre. A gain of $25\%$ at the same selling price means the effective cost price is $\frac45$. So milk : water $=4:1$, and water is $\frac15=20\%$ of the mixture.

Chapter Mock 10: Mixture and Alligation