document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1121674>Question 1121674</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Two pipes A and B, are used to fill a water tank. The empty tank is filled in 10 hours if two pipes are used together. If pipe A alone is used for 6 hours and then turned off, pipe B will .take over and finish off filling the tank in 18 hours. How long will it take each pipe alone 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 #737628 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=737628\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let A = the fill rate of pipe A<BR>\n" );
document.write( "Let B = the fill rate of pipe B<BR>\n" );
document.write( "Working together, their combined rate is A + B = 1 tank/10 h = 1/10 -> A = 1/10 - B<BR>\n" );
document.write( "Pipe A working alone will fill A*6 of a tank<BR>\n" );
document.write( "The remaining portion of the tank is filled by B in 18 h<BR>\n" );
document.write( "Thus 1 = A*6 + B*18<BR>\n" );
document.write( "1 = 6(1/10 - B) + 18B<BR>\n" );
document.write( "Solving for B gives 12B = 4/10 -> B = 1/30<BR>\n" );
document.write( "Thus A = 1/10 - 1/30 = 2/30<BR>\n" );
document.write( "So it would take A 15 hrs and B 30 hrs to fill the tank alone\r<BR>\n" );
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