Question

You need 520 mL of a 15% alcohol solution. On hand, you have a 65% alcohol mixture. How much of the 65% alcohol mixture and pure water will you need to obtain the desired solution?

You will need _____ mL of pure water and _____ mL of the 65% solution.

Answer 1

• 400 ml, 120 ml

Explanation:

Alcohol content of 15% solution:

• 0.15*520 = 78 ml

Volume of 65% solution containing 78 ml of alcohol:

• 78/0.65 = 120 ml

Required water volume to obtain 15% solution:

• 520 - 120 = 400 ml