document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=164392>Question 164392</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780495113492/algebrahomeworkh>Elementary Technical Mathematics</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A 12-quart cooling system is checked and found to be filled with a solution that is 40% antifreeze. The desired strength of the solution is 60% antifreeze. How many quarts of solution need to be drained and replaced with pure antifreeze to reach the desired strength? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #121098 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=121098\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let x=number of quarts that needs to be drained and replaced with pure antifreeze<BR>\n" );
document.write( "Now we know that the amount of pure antifreeze remaining after x amount has been drained (0.40(12-x)) plus the amount of pure antifreeze added (x) has to equal the amount of pure antifreeze in the final mixture (0.60*12).  So, our equation to solve is:\r<BR>\n" );
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document.write( "0.40(12-x)+x=0.60*12  get rid of parens (distributive law)<BR>\n" );
document.write( "4.8-0.40x+x=7.2  subtract 4.8 from each side<BR>\n" );
document.write( "4.8-4.8-0.40x+x=7.2-4.8  collect like terms<BR>\n" );
document.write( "0.60x=2.4  divide each side by 0.60<BR>\n" );
document.write( "x=4 quarts ----number of quarts that needs to be drained and replaced with pure antifreeze\r<BR>\n" );
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document.write( "CK<BR>\n" );
document.write( "0.4*8+4=7.2<BR>\n" );
document.write( "3.2+4=7.2<BR>\n" );
document.write( "7.2=7.2\r<BR>\n" );
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document.write( "Hope this helps---ptaylor </SPAN>\n" );
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