SOLUTION: At a metal melting factory, a machinist melts two barrels of metal and mixes them together. The one barrel contained metal that was 40% copper while the other barrel contained meta

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: At a metal melting factory, a machinist melts two barrels of metal and mixes them together. The one barrel contained metal that was 40% copper while the other barrel contained meta      Log On


   



Question 1028646: At a metal melting factory, a machinist melts two barrels of metal and mixes them together. The one barrel contained metal that was 40% copper while the other barrel contained metal that was 80% copper. The result was 120 pounds of metal that was 48% copper. How many pounds of metal were in the barrel that contained the 80% copper?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ =pounds of metal in the 80% copper barrel
+120+-+x+ = pounds of metal in the 40% copper barrel
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+%28+.8x+%2B+.4%2A%28+120+-+x+%29%29+%2F+120+=+.48+
+%28+.8x+%2B+48+-+.4x+%29+%2F+120+=+.48+
+.4x+%2B+48+=+.48%2A120+
+.4x+=+57.6+-+48+
+.4x+=+9.6+
+x+=+24+
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24 pounds of metal were in the barrel
that contained the 80% copper
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check:
+%28+.8x+%2B+.4%2A%28+120+-+x+%29%29+%2F+120+=+.48+
+%28+.8%2A24+%2B+.4%2A%28+120+-+24+%29%29+%2F+120+=+.48+
+%28+19.2+%2B+.4%2A96+%29+%2F+120+=+.48+
+%28+19.2+%2B+38.4+%29+%2F+120+=+.48+
+57.6+%2F+120+=+.48+
+57.6+=+57.6+
OK