How much water should be added to 20oz of a 15% solution of alcohol to dilute it to s 10% alcohol solution?

1 answer

Let the number of oz of added H2O be x.

The mass of alcohol in the solution stays the same. Only H2O is added.

0.20*15 = 0.10(20 + x)

Solve for x.

3 = 2 + 0.1x

x = 1/0.1 = 10 oz