Question

How many quarts of water must be added to 40 quarts of a 5% acid solution to dilute it to a 2% solution?

Answer 1

5% of 40 quarts results in 2 quarts of acid (38 quarts water)
x=quarts of water to be added
40+x equals the amount of 2% solution

so .02(40+x)=2 quarts
.8 + .02x = 2 quarts
.02x=2 qts - .8 =1.2 qts
.02x=1.2
x=60 qts of additional water required

solution now consist of 100 qts at 2% acid.