document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1207753>Question 1207753</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The cooling system of a certain foreign-made car has a capacity of 15 liters. If the system is filled with a mixture that is 40% antifreeze, how much of this mixture should be drained and replaced by pure antifreeze so that the system is filled with a solution that is 60% antifreeze?\r<BR>\n" );
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document.write( "Let me see.\r<BR>\n" );
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document.write( "Mixture 1 + mixture 2 = total mixture \r<BR>\n" );
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document.write( "15(0.40) + x = 0.60(x + 15)\r<BR>\n" );
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document.write( "Is this the correct set up?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #845805 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=845805\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Your setup is NOT correct.<br><BR>\n" );
document.write( "Your setup says you are mixing 15 liters of 40% antifreeze with an unknown amount of pure (100%) antifreeze to get (15+x) liters of 60% antifreeze.<br><BR>\n" );
document.write( "The capacity of the cooling system is 15 liters, so that can't be right.<br><BR>\n" );
document.write( "The x liters of pure antifreeze can only be put into the cooling system after x liters of the 40% antifreeze is drained out.  So you are mixing (15-x) liters of the 40% antifreeze with x liters of pure antifreeze to get 15 liters of 60% antifreeze:<br><BR>\n" );
document.write( "(15-x)(.40)+x(1.00)=15(.60)<br><BR>\n" );
document.write( "Solve as shown in the response from the other tutor.<br><BR>\n" );
document.write( "If formal algebra is not required, here is a solution using a quick and easy informal method that can be used to solve any 2-part mixture problem like this.<br><BR>\n" );
document.write( "You are mixing 40% antifreeze with 100% antifreeze to get 60% antifreeze.<BR>\n" );
document.write( "Look at the three percentages (on a number line, if it helps) and observe that 60% is 1/3 of the way from 40% to 100%.<BR>\n" );
document.write( "That means 1/3 of the mixture needs to be the higher percentage antifreeze.<br><BR>\n" );
document.write( "1/3 of 15 liters is 5 liters, so the mixture needs to use 5 liters of pure antifreeze.  That of course means 5 liters of the 40% antifreeze must be drained to make room for the pure antifreeze.<br><BR>\n" );
document.write( "ANSWER: 5 liters<br><BR>\n" );
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