SOLUTION: How many gallons of a 80% antifreeze solution must be mixed with 80 gallons of 25% antifreeze to get a mixture that is 70% antifreeze?

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Question 715759:
How many gallons of a 80% antifreeze solution must be mixed with 80 gallons of 25% antifreeze to get a mixture that is 70% antifreeze?
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
.80X+.25*80=.70(80+X)
.80X+20=56+.70X
.80X-.70X=56-20
.10X=36
X=36/.10
X=360 GALLONS OF 80% ANTIFREEZE IS USED.
PROOF:
.80*360+.25*80=.70(80+360)
288+20=.70*440
308=308