document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=574962>Question 574962</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose you combine ingots of 25% copper alloy and 50% copper alloy to create 40 kg of 45% copper alloy. How many kilograms of each do you need?\r<BR>\n" );
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document.write( "Select one:\r<BR>\n" );
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document.write( "a. 80 kg 25% alloy; 40 kg 25% alloy \r<BR>\n" );
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document.write( "b. 32 kg 50% alloy; 8 kg 25% alloy \r<BR>\n" );
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document.write( "c. 0 kg 25% alloy; 40 kg 50% alloy \r<BR>\n" );
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document.write( "d. 25 kg 50% alloy; 15 kg 25% alloy \r<BR>\n" );
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document.write( "I need help can't get the answer! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #369348 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=369348\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x = amount of the first solution.<BR>\n" );
document.write( "y = amount of the second solution.<BR>\n" );
document.write( "x + y = 40 kg of the combined solution.<BR>\n" );
document.write( ".25x is the amount of copper alloy in the first solution.<BR>\n" );
document.write( ".50x is the amount of copper alloy in the second solution.<BR>\n" );
document.write( ".45 * 40 is the amount of copper alloy in the combined solution.<BR>\n" );
document.write( "you have 2 equations.<BR>\n" );
document.write( "x + y = 40<BR>\n" );
document.write( ".25x + .50y = .45*40<BR>\n" );
document.write( "the first equation tells you the total amount of the new solution.<BR>\n" );
document.write( "the second equation tells you the amount of copper alloy in the new solution.<BR>\n" );
document.write( "solve these 2 equations simultaneously for your answer.<BR>\n" );
document.write( "from the first equation, solve for x to get:<BR>\n" );
document.write( "x = 40 - y<BR>\n" );
document.write( "substitute this value for x in the second equation to get:<BR>\n" );
document.write( ".25(40-y) + .5y = .45*40<BR>\n" );
document.write( "simplify to get:<BR>\n" );
document.write( ".25*40 - .25y + .5y = .45*40<BR>\n" );
document.write( "combine like terms to get:<BR>\n" );
document.write( ".25*40 + .25y = .45*40<BR>\n" );
document.write( "subtract .25*40 from both sides of the equation to get:<BR>\n" );
document.write( ".25y = .45*40 - .25*40<BR>\n" );
document.write( "factor the right side of the equation to get:<BR>\n" );
document.write( ".25y = 40*(.45-.25)<BR>\n" );
document.write( "simplify to get:<BR>\n" );
document.write( ".25y = 40*(.20)<BR>\n" );
document.write( "simplify further to get:<BR>\n" );
document.write( ".25y = 8<BR>\n" );
document.write( "divide both sides of this equation by .25 to get:<BR>\n" );
document.write( "y = 32<BR>\n" );
document.write( "since x + y = 40, this means that:<BR>\n" );
document.write( "x = 8<BR>\n" );
document.write( "you need 8 kilograms of 25% copper alloy and 32 kilograms of 50% copper alloy to get 40  kilograms of 45% copper alloy.<BR>\n" );
document.write( "8 + 32 = 40<BR>\n" );
document.write( ".25*8 + .5*32 = 2 + 16 = 18<BR>\n" );
document.write( "18 / 40 = 45% copper alloy in the new solution.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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