How many mL of alcohol and how many mL of water are needed to prepare a 35.0%

alcohol solution containing 15.0 mL

15.00 ml ROH + 27.86 ml H₂O = > 42.86 ml of solution

Explanation:

Assuming the 15.0 is the volume of alcohol ...

Vol ROH = 15.00 ml = 35% of X where X = total volume of solution

X = 15.00 ml/0.35 = 42.86 ml total volume of solution

∴ Volume of water in 42.86 ml of solution = 42.86 ml - 15.00 ml = 27.86 ml