Mixture of 20L has 24% acid, how much water do you need to make 8% acid?

Question

Mixture of 20L has 24% acid, how much water do you need to make 8% acid?

Answer 1

Chemistry:

(20 L)(24%) = (x L)(8%)

x = 60 liters, so you must add 40 liters water to the 20 liters.

 

Math:

(20L)(24%) = (20L + xL)(8%)

480 = 160 + 8x

8x = 320

x = 40 liters of water