Question

You need a 60% alcohol solution. On hand, you have a 480 mL of a 75% alcohol mixture. How much pure water will you need to add to obtain the desired solution?​

Answer 1

120 mL

Explanation:

If the 480 mL has 75% concentration, then 360 mL are alcohol. To turn the 360 into only 60%, you need to increase the amount of water.