document.write( "Question 58158: A metallurgist has one alloy containing 20% copper and another containing 70% copper. How many pounds of alloy must he use to make 50 pounds of the a third alloy containing 50% copper?\r
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Algebra.Com's Answer #39925 by ankor@dixie-net.com(22740)\"\" \"About 
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A metallurgist has one alloy containing 20% copper and another containing 70% copper. How many pounds of alloy must he use to make 50 pounds of the a third alloy containing 50% copper?
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\n" ); document.write( "This is a typical mixture problem, if you learn this method you can handle most
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\n" ); document.write( "Let x = amt of the 20% alloy, Since the resulting amt is 50 pounds we can say:
\n" ); document.write( "(50-x) = amt of the 70% alloy:
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\n" ); document.write( ".20(x) + .70(50-x) = .50(50)
\n" ); document.write( ".2x + 35 - .7x = 25
\n" ); document.write( ".2x - .7x = 25 - 35
\n" ); document.write( " -.5x = -10
\n" ); document.write( " x = -10/-.5
\n" ); document.write( " x = + 20 lb of the 20% alloy
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\n" ); document.write( "The 70% alloy = 50 - 20 = 30 lb
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\n" ); document.write( "Check:
\n" ); document.write( ".2(20) + .7(30) = .5(50)
\n" ); document.write( "4 + 21 = 25
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