Question 1191542
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You can solve the problem even more easily without algebra.<br>
Although the wording disguises the problem well, this is essentially a mixture problem: you are mixing 70% alcohol with 100% alcohol to get a mixture that is 87.5% alcohol.<br>
To solve the problem, you only need to find where the 87.5% of the final mixture lies between the 70% and 100% of the two ingredients.<br>
Simple arithmetic shows that 87.5% is 17.5/30 = 7/12 of the way from 70% to 100%; that means 7/12 of the mixture is the 100% alcohol.<br>
Then, since that 7/12 of the mixture is 7 liters, the capacity of the can is 12 liters.<br>
ANSWER: 12 liters<br>
The words of explanation make this seem like a lengthy solution; but the calculations alone are quick and easy:<br>
87.5-70=17.5
100-70=30
17.5/30=35/60=7/12
7/12 = 7/x
x=12<br>