Milk contains 10% water. What content of pure milk should be added to 20 liters of milk to reduce this to 5%?	Choose the correct choice:
A) 20 liters B) 25 liters C) 30 liters D) 15 liters E) 18 liters

Rationale: quantity of water in 20 liters = 10 % of 20 liters = 2 liters let x liters of pure milk be added . then , 2 / ( 20 + x ) = 5 / 100 5 x = 100 x = 20 liters answer is a
Answer: A