A milk man has 20 liters of milk. If he mixes 5 liters of water, which is freely available, in 20 liters of pure milk.If the cost of pure milk is Rs.18 per liter,then the profit of the milkman, when he sells all the mixture at cost price is:

Correct Answer: 25%

when the water is freely available and all the water is sold at the price of the milk, then the water gives the profit on the cost of 20 liters of milk.

 Therefore, profit percentage = (5/20) x 100 =25 %       [ Profit %= (Profit/C.P)*100]