document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=956567>Question 956567</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A pipe can fill a tank in 3 hours. Another pipe can empty the tank in 6 hours. If the tank is empty and both pipes are open, how many hours will it take to fill the tank? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #584400 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=584400\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The rate of filling of the 1st pipe is:<BR>\n" );
document.write( "[ 1 tank filled ] / [ 3 hrs ]<BR>\n" );
document.write( "-------------------------------<BR>\n" );
document.write( "The rate of emptying of the 2nd pipe is:<BR>\n" );
document.write( "-[ 1 tank emptied ] / [ 6 hrs ]<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "Notice that the emptying rate has to have<BR>\n" );
document.write( "a minus sign to make it opposite the<BR>\n" );
document.write( "filling rate<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+ ALIGN=MIDDLE  ALT=\"+1%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the rate of filling with<BR>\n" );
document.write( "both pipes open<BR>\n" );
document.write( "Add the rates to get the rate working together<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F3+-+1%2F6+=+1%2Ft+ ALIGN=MIDDLE  ALT=\"+1%2F3+-+1%2F6+=+1%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+6t+ ALIGN=MIDDLE  ALT=\"+6t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2t+-+t+=+6+ ALIGN=MIDDLE  ALT=\"+2t+-+t+=+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+6+ ALIGN=MIDDLE  ALT=\"+t+=+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "It will take 6 hrs to fill the tank<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "This makes sense because in 6 hrs, the 1st pipe<BR>\n" );
document.write( "fills the tank twice<BR>\n" );
document.write( "In that same 6 hrs, the 2nd pipe empties the<BR>\n" );
document.write( "tank once<BR>\n" );
document.write( "and you are left with 1 tank full<BR>\n" );
document.write( " \r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );