SOLUTION: Grace has 3 liters of a mixture containing 49% of boric acid. How much water must be added to make the mixture 42% boric acid?

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Question 771356: Grace has 3 liters of a mixture containing 49% of boric acid. How much water must be added to make the mixture 42% boric acid?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +w+ = liters of water to be added
+.49%2A3+=+1.47+ liters of boric acid in 49% mixture
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+1.47+%2F+%28+w+%2B+3+%29+=+.42+
+1.47+=+.42%2A%28+w+%2B+3+%29+
+1.47+=+.42w+%2B+1.26+
+.42w+=+.21+
+w+=+.5+
.5 liters of water must be added
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Check:
+1.47+%2F+%28+.5+%2B+3+%29+=+.42+
+1.47+=+.42%2A3.5+
+1.47+=+1.47+
OK