Answer
0.9516 grams / mL (50.00 has 4 sig digs.)
Remark
You have a couple of extraneous numbers there. You don't care about anything except the mass of the flask + water/alcohol mixture (88.219 grams). and the mass of the flask (40.638 grams)
Formulas
Solution
mass water/alcohol mixture = 88.219 - 40.638 = 47.581