Is this the exact wording of the problem? There's a lot of ambiguity.
I read it as, if the scientist starts with X g of material, 42.2% of X is in solution (with 250 g water) at 80 C and 11.1% of X is in solution (250 g water) at 20 C. From this you can deduce the fraction of material that's in the precipitate at each temperature, and therefore the difference. But this would be in terms of X. To get an absolute number you'd need either X or the solubility of X at either temperature (since you're given the amount of water).