Verified answer

first find the molecular weight of the entire molecule, so how many grams are in one mol of substance.

then find the molecular weight of just the water, and remember to factor that 5 in front, so you'll have 10 hydrogen and 5 oxygen.

when you find the molecular weight of the pentahydrate on its own divide that by the molecular weight of the whole molecule and then multiply it by 100%

a nice way to look at it is:

5 H20 // CuSO4.5H2O *100%