SOLUTION: Question: How much pure alcohol should be added to 30 quarts of a 15% solution of alcohol to give a solution that is 60% alcohol? *Set the equation up in terms of alcohol and sol

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Question 896286: Question: How much pure alcohol should be added to 30 quarts of a 15% solution of alcohol to give a solution that is 60% alcohol?
*Set the equation up in terms of alcohol and solve.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = quarts of alcohol to be added
+.15%2A30+=+4.5+ quarts of alcohol in 15% solution
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+%28+a+%2B+4.5+%29+%2F+%28+a+%2B+30+%29+=+.6+
+a+%2B+4.5+=+.6%2A%28+a+%2B+30+%29+
+a+%2B+4.5+=+.6a+%2B+18+
+.4a+=+13.5+
+a+=+33.75+
33.75 quarts of alcohol needs to be added
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check:
+%28+a+%2B+4.5+%29+%2F+%28+a+%2B+30+%29+=+.6+
+%28+33.75+%2B+4.5+%29+%2F+%28+33.75+%2B+30+%29+=+.6+
+38.25+%2F+63.75+=+.6+
+38.25+=+.6%2A63.75+
+38.25+=+38.25+
OK