document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=339103>Question 339103</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Pipe A can fill a tank in 4h. Pipe B can fill the tank in 9 h less than the time it takes pipe C, a drain pipe, to empty the tank. When all 3 pipes are open, it takes 2h to fill the tank. How much time is required for pipe c to empty the tank if pipes A and B are closed.\r<BR>\n" );
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document.write( "thank you for your help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #243066 by </B><A HREF=/tutors/aboutme.mpl?userid=jrfrunner><B>jrfrunner(365)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jrfrunner><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=jrfrunner><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=243066\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given<BR>\n" );
document.write( "Pipe A fills tank in 4 hours<BR>\n" );
document.write( "Pipe C empties tank in C hours<BR>\n" );
document.write( "Pipe B fills tank in C-9 hours<BR>\n" );
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document.write( "this means that every hour<BR>\n" );
document.write( "Pipe A filles   1/4 of tank<BR>\n" );
document.write( "Pipe C empties  1/c of tank<BR>\n" );
document.write( "Pipe B fills 1/(c-9) of tank<BR>\n" );
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document.write( "When all pipes are open (ie working together) they fill the tank in 2 hours<BR>\n" );
document.write( "soo.....<BR>\n" );
document.write( "\"every hour\", working together 1/2 the tank is filled.<BR>\n" );
document.write( "Pipe A + pipe B -Pipe C =<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2F4%29%2B1%2F%28c-9%29-1%2Fc=1%2F2 ALIGN=MIDDLE  ALT=\"%281%2F4%29%2B1%2F%28c-9%29-1%2Fc=1%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > solve for c<BR>\n" );
document.write( "--<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F%28c-9%29-1%2Fc=1%2F2-1%2F4=1%2F4 ALIGN=MIDDLE  ALT=\"1%2F%28c-9%29-1%2Fc=1%2F2-1%2F4=1%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" >  subtract 1/4 from both sides<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c%2F%28c%2A%28c-9%29%29-%28c-9%29%2F%28%28c-9%29%2Ac%29=1%2F4 ALIGN=MIDDLE  ALT=\"c%2F%28c%2A%28c-9%29%29-%28c-9%29%2F%28%28c-9%29%2Ac%29=1%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" >  get common denominator<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28c-%28c-9%29%29%2F%28c%2A%28c-9%29%29=1%2F4 ALIGN=MIDDLE  ALT=\"%28c-%28c-9%29%29%2F%28c%2A%28c-9%29%29=1%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" >   <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%2F%28c%5E2-9%2Ac%29=1%2F4 ALIGN=MIDDLE  ALT=\"9%2F%28c%5E2-9%2Ac%29=1%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" >  combine and distribute terms<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36=c%5E2-9c ALIGN=MIDDLE  ALT=\"36=c%5E2-9c\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0=c%5E2-9%2Ac-36 ALIGN=MIDDLE  ALT=\"0=c%5E2-9%2Ac-36\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "factor<BR>\n" );
document.write( "0=(c-12)*(c+3)<BR>\n" );
document.write( "so c=12, or c=-3, since solution must be positive c=-3 is extraneous<BR>\n" );
document.write( "answer:  c=12<BR>\n" );
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document.write( "You could use use quadratic solution, a=1,b=-9, c=-36<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c=%289%2Bsqrt%28%28-9%29%5E2-4%2A1%2A%28-36%29%29%29%2F%282%2A1%29 ALIGN=MIDDLE  ALT=\"c=%289%2Bsqrt%28%28-9%29%5E2-4%2A1%2A%28-36%29%29%29%2F%282%2A1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c=%289-sqrt%28%28-9%29%5E2-4%2A1%2A%28-36%29%29%29%2F%282%2A1%29 ALIGN=MIDDLE  ALT=\"c=%289-sqrt%28%28-9%29%5E2-4%2A1%2A%28-36%29%29%29%2F%282%2A1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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