Fresh grapes contain 85% water by weight and raisins obtained by drying fresh grapes contain 25% water by weight. How many kgs of fresh grapes are needed to get 20kgs of raisins?  Pick one
A) 75 kgs B) 64 kgs C) 100 kgs D) 65 kgs E) 70 kgs

Rationale: the weight of non - water in 20 kg of dried grapes ( which is 100 - 25 = 75 % of whole weight ) will be the same as the weight of non - water in x kg of fresh grapes ( which is 100 - 85 = 15 % of whole weight ) , so 20 * 0.75 = x * 0.15 - - > x = 100 . answer : c
Answer: C