document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=745076>Question 745076</A>: <I><SPAN STYLE=\"word-break: break-all;\"> One pipe can fill a tank in 5 hours and another pipe can fill the same tank in 4 hours. A drainpipe can empty the full content of the tank in 20 hours. With all the three pipes open, how long 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 #453715 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=453715\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> One pipe can fill a tank in 5 hours and another pipe can fill the same tank in 4 hours. A drainpipe can empty the full content of the tank in 20 hours. With all the three pipes open, how long will it take to fill the tank?<BR>\n" );
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document.write( "In each hour, the 1st pipe adds 1/5 of the tank, the 2nd adds 1/4 of the tank, and the drain adds -1/20 of the tank.<BR>\n" );
document.write( "--> (1/5 + 1/4 - 1/20) tank/hour<BR>\n" );
document.write( "Hours/tank = 1/(1/5 + 1/4 - 1/20)<BR>\n" );
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