SOLUTION: How many gallons of a 90​% antifreeze solution must be mixed with 100 gallons of 15​% antifreeze to get a mixture that is 80% ​antifreeze? Use the​ six-step

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Question 1092268: How many gallons of a 90​% antifreeze solution must be mixed with 100 gallons of 15​% antifreeze to get a mixture that is 80% ​antifreeze? Use the​ six-step method.
Answer by josgarithmetic(39628) About Me  (Show Source):
You can put this solution on YOUR website!
x, how much of 90% antifreeze

%2890x%2B15%2A100%29%2F%28x%2B100%29=80
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90x%2B1500=80%28x%2B100%29
9x%2B150=8%28x%2B100%29
9x%2B150=8x%2B800
x=800-150
highlight_green%28x=650%29, gallons of the 90% antifreeze