Question 956136
Do it like this one. Only the numbers are different.      
-----------     

Amanda wants to make 8 gal. of a 20% saline solution by mixing together a 56%
saline solution and a 8% saline solution. How much of each solution must she
use?      
================      
e = amount of 8%      
f = amount of 56%   

---      
e+ f = 8 (total solution)      
8e + 56f = 20*8 (total saline)    

---      
e+ f = 8      
e + 7f = 20      
------------ Subtract      
-6f
= -12      
f = 2      
e = 6