Acid solution mixtures???

Question

How much pure acid should be mixed with 5 gallons of a 60% acid solution in order to get an 80% acid solution? 

Answer 1

5 gallons of a 60% solution contains 3 gallons of acid and 2 of water.  Let x = gallons of pure acid added.  The overall concentration is:

 

(3+x)/(5+x) = .80/1   cross multiply and solve

 

4 +.80x = 3 + x

 

.20x = 1

 

x = 5