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Question from jyoti, a student:

Fresh grapes contain 90% water by weight while dried grapes contain 20 % water by weight. what will be the weight of dry graprs available from 20kg of fresh grapes?

Hello Jyoti.

You can solve this problem with algebra:

90% of the weight of the fresh grapes is water, so 10% is not water.

10% × 20kg = 2kg of totally waterless grapes.

"Dried" grapes contain 20% water. So 80% of the weight of "dried" grapes is not water.

80% × DGW = 2kg, where DGW is the dried grape weight.

So DGW = 2kg / 80%. The equivalent weight in "dried" grapes is 2.5kg.

Hope this helps,


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