Fresh grapes contain 90% water while dry grapes contain 20% water. What is the weight of dry grapes obtained from 20 kg fresh grapes?
The weight of non-water in 20 kg of fresh grapes (which is 100-90=10% of total weight) will be the same as the weight of non-water in x kg of dried grapes (which is 100-20=80% of total weight).
20*0.1 = x*0.8
x = 2.5
The correct option is C.