question_answer

A dishonest milkman professes to sell his milk at cost price but he mixes it with water and there by gains 25%. The percentage of water in the mixture is

A) 25%

B)  20%

C)  15%    

D)  30%

Correct Answer: B

Solution :

Let CP of 1 L milk be Rs. 1

Then, SP of 1 L mixture = Rs. 1 gain = 25%

CP of 1 L mixture = Rs. \[\left( \frac{100}{125}\times 1 \right)\]= Rs. \[\frac{4}{5}\]

CP of 1 L of pure milk CP of 1 L of water

\[\therefore \] Milk : Water \[=\frac{4}{5}:\frac{1}{5}=4:1\]

Hence, percentage of water in the mixture

\[=\left( \frac{1}{5}\times 100 \right)%=20%\]