Question 608819
Solution I --12%---x gal
Solution II--20%---(6-x)gal

Mixture total ---- 18% -----6 gal

12%*x+(6-x)*20%= 6*18%

multiply equation by 100

12x+(6-x)*20 = 108

12x+120-20x=108

12x-20x=108-120
-8x=-12x
/-8
x=-12/8
x=3/4 gallons  --- 6% solution

Balance of 6 gallons is 20% solution
6-3/4
= 5 1/4 gallons