a solid substance a is soluble in water to the extent of 10 mg/ml of water at 25oc and 100 mg/ml of water at 100oc. you have a sample that contains 100 mg of a and 25 mg of an impurity b. a and b have the same solubility behavior. if one 10ml portion of water was used for the recrystallization, what was the % recovery of a