A mixture of 50 litres of milk and water contains 10% water. How many litres of water should be added to the mixture so that the mixture contains 15% water?
Options:
A) 15 B) 20 C) 25 D) 30 E) 10

Rationale: quantity of milk in the mixture = 90 / 100 ( 50 ) = 45 litres . after adding water , milk would form 60 % of the mixture . hence , if quantity of mixture after adding x liters of water , ( 60 ) / 100 x = 45 = > x = 75 hence 75 - 50 = 25 litres of water must be added . answer : c
Answer: C