In 70 liters of a mixture of milk and water ,the quantity of water is 10%. how much water should be added so that new mixture may 25% water.	Pick:
A) 14  B) 15  C) 16  D) 17  E) 18

Rationale: there are 10 % of water in 70 l - - > there are 7 l of waters ; after x liters of water is added amount of water becomes ( 7 + x ) liters , which on the other hand is 1 / 4 th ( 25 % ) of new ( 70 + x ) liters of mixture : 7 + x = 1 / 4 * ( 70 + x ) - - > 28 + 4 x = 70 + x - - > x = 14 answer : a
Answer: A