document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=436132>Question 436132</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Word problem.\r<BR>\n" );
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document.write( "It takes 60 minutes to fill a pond with water alone.<BR>\n" );
document.write( "It takes 80 minutes to drain a pond of water alone.\r<BR>\n" );
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document.write( "How long will it take to fill the pond while it is being drained at the same time? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #853277 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39720)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=853277\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "               rate         time        amount\r\n" );
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document.write( "filling        1/60         60           1\r\n" );
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document.write( "draining       1/80         80           1\r\n" );
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document.write( "combined    1/60-1/80        x           1\r\n" );
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document.write( "The rates are additive, but need to understand draining is negative while filling is positive.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F60-1%2F80 ALIGN=MIDDLE  ALT=\"1%2F60-1%2F80\"   DISABLED_style= \"max-width:90%; height:auto;\" > ponds per minute\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F240-3%2F240 ALIGN=MIDDLE  ALT=\"4%2F240-3%2F240\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F240 ALIGN=MIDDLE  ALT=\"1%2F240\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "That is 1 pond in 240 minutes, or 240 minutes to fill the 1 pond with both flows opened. </SPAN>\n" );
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