document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=972456>Question 972456</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A tank can be filled by one pipe in four hours and by a second pipe in six hours; and when it is full, the tank can be drained by a third pipe in three hours. If the tank is empty and all three pipes are open, in how many hours will the tank be filled?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #594778 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=594778\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Add the rates of filling and subtract the<BR>\n" );
document.write( "rate of draining for the 3 pipes to get<BR>\n" );
document.write( "the rate of filling with all 3 open<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "rates of filling:<BR>\n" );
document.write( "[ 1 tank filled ] / [ 4 hrs ]<BR>\n" );
document.write( "[ 1 tank filled ] / [ 6 hrs ]<BR>\n" );
document.write( "rate of draining:<BR>\n" );
document.write( "[ 1 tank drained ] / [ 3 hrs ]<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = time in hrs for the tank to be<BR>\n" );
document.write( "filled with all 3 pipes open<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F4+%2B+1%2F6+=+1%2F3+=+1%2Ft+ ALIGN=MIDDLE  ALT=\"+1%2F4+%2B+1%2F6+=+1%2F3+=+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=+12t+ ALIGN=MIDDLE  ALT=\"+12t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3t+%2B+2t+-+4t+=+12+ ALIGN=MIDDLE  ALT=\"+3t+%2B+2t+-+4t+=+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+12+ ALIGN=MIDDLE  ALT=\"+t+=+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "In 12 hrs, the tank will be filled with<BR>\n" );
document.write( "all 3 pipes open<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.25+%2B+.1667+-+.333+=+.08333+ ALIGN=MIDDLE  ALT=\"+.25+%2B+.1667+-+.333+=+.08333+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.0834+=+.0833+ ALIGN=MIDDLE  ALT=\"+.0834+=+.0833+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK -error due to rounding off\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );