SOLUTION: How many gallons of a 70% antifreeze solution must be mixed with 70 gallons of 25% antifreeze to get a mixture that is 60% antifreeze? x= 70% antifreeze x+70= 25%antifreeze

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Question 708649: How many gallons of a 70% antifreeze solution must be mixed with 70 gallons of 25% antifreeze to get a mixture that is 60% antifreeze?
x= 70% antifreeze
x+70= 25%antifreeze
x+.60(x+70)=unknown this is were I am lost
x+.60x+42
1.6x+42
Answer by josgarithmetic(39799) About Me  (Show Source):
You can put this solution on YOUR website!
Taking the format of quantity*concentration,
x%2A70%2B70%2A25 = actual antifreeze substance


%28x%2A70%2B70%2A25%29%2FV=60, the desired concentration is 60%. Volume V is still unknown.


Known also is that this starts with 70 gallons of one of the antifreeze solutions, so,
x+70=V, which we might have used already in setting up the "60%" equation.

Let's do that, already:
%28x%2A70%2B70%2A25%29%2F%28x%2B70%29=60
THAT is what we want to solve; solve for x.