A dishonest milkman professes to sell his milk at cost price but he mixes it…
2023
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:
- A.
25%
- B.
64 1/4%
- C.
23%
- D.
20%
Attempted by 13 students.
Show answer & explanation
Correct answer: D
Key idea: the milkman sells the mixture at the cost price of pure milk, and a 25% gain means the cost price of the mixture is lower than that selling price.
Assume the cost price of 1 litre of pure milk = 1.
The milkman sells 1 litre of the mixture at 1 (he sells at cost price of milk). Since he gains 25%, the cost price of 1 litre of the mixture = 1 ÷ 1.25 = 4/5 = 0.8.
This 0.8 is the cost of milk present in 1 litre of mixture. Since 1 litre of pure milk costs 1, the fraction of milk in the mixture = 0.8/1 = 4/5 = 80%.
Therefore the fraction of water = 1 - 4/5 = 1/5 = 20%.
Answer: 20%.