Question 947949
Do it like this one. Only the numbers are different. 
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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? 
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e = amount of 8% 
f = amount of 56% 
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e+ f = 8 (total solution) 
8e + 56f = 20*8 (total saline) 
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e+ f = 8 
e + 7f = 20 
------------ Subtract 
-6f = -12 
f = 2 
e = 6