document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1112012>Question 1112012</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How much of an alloy that is 20% copper should be mixed with 100 ounces of an alloy that is 70% copper in order to get an alloy that is 40% copper. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #727035 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=727035\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let x equal the amount of the alloy that is 20% copper.\r<BR>\n" );
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document.write( "the amount of copper in that alloy is equal to .2 * x.\r<BR>\n" );
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document.write( "the amount of copper that is in the alloy that is 70% copper would be .7 * 100 = 70.\r<BR>\n" );
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document.write( "when you add x ounces to 100 ounces, you get a total of x + 100 ounces in the final mixture.\r<BR>\n" );
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document.write( "that final mixture will contain 40% copper.\r<BR>\n" );
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document.write( "the amount of copper that is in that final mixture will be .4 * (x + 100).\r<BR>\n" );
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document.write( "your equation becomes:\r<BR>\n" );
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document.write( ".2 * x + .7 * 100 = .4 * (100 + x).\r<BR>\n" );
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document.write( "simplify to get:\r<BR>\n" );
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document.write( ".2 * x + 70 = 40 + .4 * x\r<BR>\n" );
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document.write( "subtract .4 * x from both sides of the equation and subtract 70 from both sides of the equation to get:\r<BR>\n" );
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document.write( ".2 * x - .4 * x = 40 - 70\r<BR>\n" );
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document.write( "simplify to get:\r<BR>\n" );
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document.write( "-.2 * x = -30\r<BR>\n" );
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document.write( "divide both sides of this equation by -.2 to get:\r<BR>\n" );
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document.write( "x = -30 / -.2\r<BR>\n" );
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document.write( "this results in x = 150.\r<BR>\n" );
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document.write( "you would need to mix 150 ounces of 20% copper with 100 ounces of 70% copper to get a 250 ounce mixture that is 40% copper.\r<BR>\n" );
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document.write( ".2 * 150 = 30 ounces of copper in the 20% mixture.<BR>\n" );
document.write( ".7 * 100 = 70 ounces of copper in the 70% mixture.\r<BR>\n" );
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document.write( "final mixture is 150 + 100 = 250 ounces<BR>\n" );
document.write( "total copper in the final mixture is 30 + 70 = 100 ounces.\r<BR>\n" );
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document.write( "100 / 250 = .4 which is equal to 40% copper in the final mixture.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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