document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1068609>Question 1068609</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A paddle boat can move at a speed of 8 km/h in still water. The boat is paddled 4 km downstream in a river in the same time it takes to go 2 km upstream. What is the speed of the river? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #683838 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=683838\">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( "c   speed of stream current --- UNKNOWN in this example\r\n" );
document.write( "r   speed of paddle boat if no current--- 8\r\n" );
document.write( "t   time either direction -- UNKNOWN in this example\r\n" );
document.write( "d   downstream distance ---  4\r\n" );
document.write( "u   upstream distance  --- 2\r\n" );
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document.write( "                  SPEED        TIME       DISTANCE\r\n" );
document.write( "DOWNSTREAM        r+c           t           d\r\n" );
document.write( "UPSTREAM          r-c           t           u\r\n" );
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document.write( "Question asks for c, the river current speed.\r<BR>\n" );
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document.write( "Basic constant travel rates rule, RT=D to relate rate, time, distance.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%2F%28r%2Bc%29=u%2F%28r-c%29 ALIGN=MIDDLE  ALT=\"d%2F%28r%2Bc%29=u%2F%28r-c%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >---solve this for c in terms of the other variables.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%28r-c%29=u%28r%2Bc%29 ALIGN=MIDDLE  ALT=\"d%28r-c%29=u%28r%2Bc%29\"   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=dr-dc=ur%2Buc ALIGN=MIDDLE  ALT=\"dr-dc=ur%2Buc\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=dr-ur=uc%2Bdc ALIGN=MIDDLE  ALT=\"dr-ur=uc%2Bdc\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=dr-ur=c%28u%2Bd%29 ALIGN=MIDDLE  ALT=\"dr-ur=c%28u%2Bd%29\"   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%28c=%28dr-ur%29%2F%28u%2Bd%29%29 ALIGN=MIDDLE  ALT=\"highlight%28c=%28dr-ur%29%2F%28u%2Bd%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >----substitute the given values into this formula. </SPAN>\n" );
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