A dishonest milkman professes to sell his milk at cost price but he mixes it with water

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

  1. 4%
  2. 6.25%
  3. 20%
  4. 25%

Answer

Let C.P. of 1 litre milk = Re. 1 (Dearer)

S.P. of 1 litre of mixture = Re. 1

Gain = 25%

C.P. of 1 litre of mixture = Re. (100/125) x 1 = 4/5 (Mean)

C.P. of water = Re. 0 (Cheaper)

Ratio of milk to water = 4/5 - 0 : 1 - 4/5 = 4/5 : 1/5

Percentage of water in the mixture = (1/5) x 100% = 20%

The correct option is C.