document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=621623>Question 621623</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Two drains takes 9 hours each to completely remove the water from similar-sizes(same volume) pools. The first drain was opened at 6 a.m. Two hours after, the second drain is opened. At what time will the remaining volume in the second pool be three times the remaining volume in the first pool?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #390925 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=390925\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Each drain empties at the rate of (1/9)V per hour where V is the volume of each pool\r<BR>\n" );
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document.write( "When the second drain is opened, the first pool has emptied 2*(1/9)V leaving V-(2/9)V=(7/9)V yet to be emptied.\r<BR>\n" );
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document.write( "Let t=number of hours it takes AFTER the second drain is opened for the second pool to have three time the remaining volume of the first pool\r<BR>\n" );
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document.write( "Amount of water remaining in the first pool after t hours=(7/9)V-(t/9)V<BR>\n" );
document.write( "Amount of water remaining in the second pool after t hours V-(t/9)V and this is three time the remaining volume of the first pool, soooo:<BR>\n" );
document.write( "3{(7/9)V-(t/9)V}=V-(t/9)V simplify<BR>\n" );
document.write( "(21/9)V-(3t/9)V=V-(t/9)V<BR>\n" );
document.write( "(21/9)V-V=(3t/9)V-(t/9)V<BR>\n" );
document.write( "(12/9)V=(2t/9)V divide each side by V and multiply each side by 9<BR>\n" );
document.write( "2t=12<BR>\n" );
document.write( "t=6 hr--number of hours it takes AFTER the second drain is opened<BR>\n" );
document.write( "Second drain is opened at 8 am; 8 am plus 6 hours=2 pm  --the time at which the second pool has 3 times the volume of the first pool\r<BR>\n" );
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document.write( "CK<BR>\n" );
document.write( "In 6 hours the first pool has drained 6+2=8/9 its volume, leaving (1/9)V<BR>\n" );
document.write( "In 6 hours the second pool has drained 6/9 its volume leaving (3/9)V and this is three times more that (1/9)V\r<BR>\n" );
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document.write( "Hope this helps---ptaylor<BR>\n" );
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