Question

How many gallons of a 70​% antifreeze solution must be mixed with 100 gallons of 25​% antifreeze to get a mixture that is 60​% ​antifreeze? Use the​ six-step method.

You need ___ gallons.

(Round to the nearest whole​ number.)

Answer 1

Let n be the amount of 70% antifreeze. Then:
.7n+.25(100)=.6(100+n)
.7n+25=60+.6n
.1n=35
n=350 gallons of 70% antifreeze is needed
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