document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1000750>Question 1000750</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An inlet pipe on a swimming pool can be used to fill the pool in 20 hours. The drain pipe can be used to empty the pool in 21 hours. If the pool is 1/3 filled and then the inlet pipe and drain pipe are opened, how long from that time will it take to fill the pool?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #618104 by </B><A HREF=/tutors/aboutme.mpl?userid=addingup><B>addingup(3677)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=addingup><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=addingup><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=618104\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In 1 hour the pool fills 1/20<BR>\n" );
document.write( "In 1 hour the pool empties 1/21<BR>\n" );
document.write( "1/20-1/21= 1/3T Multiply all sides by 420 (20*21, it's the common denominator)<BR>\n" );
document.write( "21-20= 140/T<BR>\n" );
document.write( "1= 140/T Invert both terms:<BR>\n" );
document.write( "1/1= T/140 Multiply both sides times 140:<BR>\n" );
document.write( "140= T You need 140 hours </SPAN>\n" );
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