document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=559646>Question 559646</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a car radiator has a capacity of 16 quartz and is filled with a 25% antifreeze solution. how much must be drained off and replaced with pure antifreeze to obtain a 40% antifreeze solution? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #844475 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=844475\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "The \"draining off\" and \"replacing\" in the problem only complicates the process of solving the problem.  Essentially, you are simply mixing a 25% antifreeze solution with a 100% antifreeze solution to obtain 16 quarts of 40% antifreeze.<br><BR>\n" );
document.write( "The question asks for the amount of pure antifreeze to be used.  So<br><BR>\n" );
document.write( "x = quarts of 100% antifreeze<BR>\n" );
document.write( "16-x = quarts of 25% antifreeze<br><BR>\n" );
document.write( "The mixture is 40% antifreeze:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1.00%28x%29%2B.25%2816-x%29=.40%2816%29 ALIGN=MIDDLE  ALT=\"1.00%28x%29%2B.25%2816-x%29=.40%2816%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "I leave it to you to solve the problem by that formal algebraic method.  As shown the the other tutors, the answer is 3.2 quarts.<br><BR>\n" );
document.write( "Here is an informal method that can be used to solve any 2-part mixture problem like this.<br><BR>\n" );
document.write( "The three percentages in the problem are 25, 40, and 100.  Picture (in your mind, or on paper if needed) those three percentages on a number line.  Then observe/calculate that 40 is 15/75 = 1/5 of the way from 25 to 100.  That means 1/5 of the mixture is the 100% antifreeze.<br><BR>\n" );
document.write( "1/5 of 16 quarts is 3.2 quarts.<br><BR>\n" );
document.write( "ANSWER: 3.2 quarts<br><BR>\n" );
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