document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=987007>Question 987007</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A Johnson motorboat goes 5 miles upstream in the same time it requires to go 7 miles downstream. If the river flows at 2mph, find the speed of the boat in still water.<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 #607822 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39617)</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=607822\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> More general:<BR>\n" );
document.write( "A Johnson motorboat goes <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bu%5D ALIGN=MIDDLE  ALT=\"d%5Bu%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > miles upstream in the same time it requires to go <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bd%5D ALIGN=MIDDLE  ALT=\"d%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > miles downstream. If the river flows at <i>s</i> mph, find the speed <i>r</i> of the boat in still water.\r<BR>\n" );
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document.write( "Direction         rate     time    distance\r\n" );
document.write( "upstream          r-c       t      <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bu%5D ALIGN=MIDDLE  ALT=\"d%5Bu%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r\n" );
document.write( "downstream        r+c       t      <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bd%5D ALIGN=MIDDLE  ALT=\"d%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r\n" );
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document.write( "Direction         rate       time    distance\r\n" );
document.write( "upstream          r-c       <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bu%5D%2F%28r-c%29 ALIGN=MIDDLE  ALT=\"d%5Bu%5D%2F%28r-c%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >      <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bu%5D ALIGN=MIDDLE  ALT=\"d%5Bu%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r\n" );
document.write( "downstream        r+c       <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bd%5D%2F%28r%2Bc%29 ALIGN=MIDDLE  ALT=\"d%5Bd%5D%2F%28r%2Bc%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >      <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%5Bd%5D ALIGN=MIDDLE  ALT=\"d%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r\n" );
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document.write( "The time quantities were described as equal.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28d%5Bu%5D%2F%28r-c%29=d%5Bd%5D%2F%28r%2Bc%29%29 ALIGN=MIDDLE  ALT=\"highlight_green%28d%5Bu%5D%2F%28r-c%29=d%5Bd%5D%2F%28r%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Their reciprocals are also equal (not the only strategy)...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28r-c%29%2Fd%5Bu%5D=%28r%2Bc%29%2Fd%5Bd%5D ALIGN=MIDDLE  ALT=\"%28r-c%29%2Fd%5Bu%5D=%28r%2Bc%29%2Fd%5Bd%5D\"   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=%28r-c%29d%5Bd%5D=%28r%2Bc%29d%5Bu%5D ALIGN=MIDDLE  ALT=\"%28r-c%29d%5Bd%5D=%28r%2Bc%29d%5Bu%5D\"   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=r%2Ad%5Bd%5D-c%2Ad%5Bd%5D=r%2Ad%5Bu%5D%2Bc%2Ad%5Bu%5D ALIGN=MIDDLE  ALT=\"r%2Ad%5Bd%5D-c%2Ad%5Bd%5D=r%2Ad%5Bu%5D%2Bc%2Ad%5Bu%5D\"   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=rd%5Bd%5D-rd%5Bu%5D=cd%5Bu%5D%2Bcd%5Bd%5D ALIGN=MIDDLE  ALT=\"rd%5Bd%5D-rd%5Bu%5D=cd%5Bu%5D%2Bcd%5Bd%5D\"   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=r%28d%5Bd%5D-d%5Bu%5D%29=cd%5Bu%5D%2Bcd%5Bd%5D ALIGN=MIDDLE  ALT=\"r%28d%5Bd%5D-d%5Bu%5D%29=cd%5Bu%5D%2Bcd%5Bd%5D\"   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=highlight%28r=%28cd%5Bu%5D%2Bcd%5Bd%5D%29%2F%28d%5Bd%5D-d%5Bu%5D%29%29 ALIGN=MIDDLE  ALT=\"highlight%28r=%28cd%5Bu%5D%2Bcd%5Bd%5D%29%2F%28d%5Bd%5D-d%5Bu%5D%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Evaluate the boat speed r according to<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28d%5Bu%5D=5%2Cd%5Bd%5D=7%2Cc=2%29 ALIGN=MIDDLE  ALT=\"system%28d%5Bu%5D=5%2Cd%5Bd%5D=7%2Cc=2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >. </SPAN>\n" );
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