document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1208989>Question 1208989</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A 20-pound bag of Economy brand cement mix contains 25% cement and 75% sand. How much pure cement must be added to produce a cement mix that is 40% cement?\r<BR>\n" );
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document.write( "I think the equation should look like this:\r<BR>\n" );
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document.write( "%•amount + %•amount = %(mixture)\r<BR>\n" );
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document.write( "0.25(20) + 0.75(x) = 0.40(x + 20)\r<BR>\n" );
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document.write( "Is this correct? \r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #847537 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52781)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=847537\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .\r<BR>\n" );
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document.write( "A 20-pound bag of Economy brand cement mix contains 25% cement and 75% sand. <BR>\n" );
document.write( "How much pure cement must be added to produce a cement mix that is 40% cement?\r<BR>\n" );
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document.write( "I think the equation should look like this:\r<BR>\n" );
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document.write( "%•amount + %•amount = %(mixture)\r<BR>\n" );
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document.write( "0.25(20) + 0.75(x) = 0.40(x + 20)\r<BR>\n" );
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document.write( "Is this correct? <BR>\n" );
document.write( "~~~~~~~~~~~~~~~~~~~~~~~\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This is wrong.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I will not explain, why it is wrong.\r<BR>\n" );
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document.write( "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I will write a correct solution, instead.\r<BR>\n" );
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document.write( "<PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "Assume you add x pounds of pure cement.\r\n" );
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document.write( "Now the total mass is 20+x pounds; the portion of the pure cement is  0.25*20+x  pounds.\r\n" );
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document.write( "You want\r\n" );
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document.write( "    0.25*20 + x = 0.4*(20+x)  pounds.\r\n" );
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document.write( "It is your setup equation to solve and to find x.\r\n" );
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document.write( "Now I solve it for you step by step.  Watch my steps.\r\n" );
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document.write( "    5 + x = 8 + 0.4x,\r\n" );
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document.write( "    x - 0.4x = 8 - 5,\r\n" );
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document.write( "    0.6x = 3,\r\n" );
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document.write( "       x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3%2F0.6 ALIGN=MIDDLE  ALT=\"3%2F0.6\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2F6 ALIGN=MIDDLE  ALT=\"30%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 5 pounds  of the pure cement to add  (rounded).    <U>ANSWER</U>\r\n" );
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document.write( "Solved.\r<BR>\n" );
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