SOLUTION: How many pounds of pure alcohol must be added to 20 pounds of an 80% pure alcohol to produce an 85% pure alcohol? 0.80(20) = 0.85 (20 + x) (100)0.80(20) = (100)0.85 (20 + x)

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: How many pounds of pure alcohol must be added to 20 pounds of an 80% pure alcohol to produce an 85% pure alcohol? 0.80(20) = 0.85 (20 + x) (100)0.80(20) = (100)0.85 (20 + x)       Log On

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Question 730666: How many pounds of pure alcohol must be added to 20 pounds of an 80% pure alcohol to produce an 85% pure alcohol?
0.80(20) = 0.85 (20 + x)
(100)0.80(20) = (100)0.85 (20 + x)
80(20) = 85(20+x)
1600 = 1700 + 85x
1600 - 1700 = 1700 + 85x - 1700
-100 = 85x
-100/85 = 85x/85
-1.18 = x
The answer in the book is 6.66lbs.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+.8%2A20+=+16+ pounds of alcohol originally in solution
Let +x+ = pounds of alcohol to be added
+%28+x+%2B+16+%29+%2F+%28+x+%2B+20+%29+=+.85+
+x+%2B+16+=+85%2A%28+x+%2B+20+%29%0D%0A%7B%7B%7B+x+%2B+16+=+.85x+%2B+17+
+.15x+=+1+
+x+=+6.667+
6.66 pounds of alcohol need to be added