document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=831391>Question 831391</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this equation: <BR>\n" );
document.write( "In going over a round trip of 40 km each way, it takes a course travelling 12 kph in still water, having a total time of 7 hours and a half. What was the rate of the river current?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #501341 by </B><A HREF=/tutors/aboutme.mpl?userid=KMST><B>KMST(5328)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=KMST><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=KMST><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=501341\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Your boat travels at 12 kilometers per hour in still water.<BR>\n" );
document.write( "In a river with a current flowing at a speed of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x ALIGN=MIDDLE  ALT=\"x\"   DISABLED_style= \"max-width:90%; height:auto;\" > kilometers per hour,<BR>\n" );
document.write( "the boat will advance (as seen from the shore) at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2812-x%29 ALIGN=MIDDLE  ALT=\"%2812-x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > kph when going upstream, against the current.<BR>\n" );
document.write( "When going downstream, the boat will move at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2812%2Bx%29 ALIGN=MIDDLE  ALT=\"%2812%2Bx%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > kph relative to the shore.<BR>\n" );
document.write( "The 40 kilometer trip upstream will take<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2F%2812-x%29 ALIGN=MIDDLE  ALT=\"40%2F%2812-x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > hours.<BR>\n" );
document.write( "The 40 kilometer trip downstream will take<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2F%2812%2Bx%29 ALIGN=MIDDLE  ALT=\"40%2F%2812%2Bx%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > hours.<BR>\n" );
document.write( "Adding those times we would get the total time of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7.5 ALIGN=MIDDLE  ALT=\"7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" > hours, so our equation is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2F%2812-x%29%2B40%2F%2812%2Bx%29=7.5 ALIGN=MIDDLE  ALT=\"40%2F%2812-x%29%2B40%2F%2812%2Bx%29=7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " <BR>\n" );
document.write( "Solving:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2F%2812-x%29%2B40%2F%2812%2Bx%29=7.5 ALIGN=MIDDLE  ALT=\"40%2F%2812-x%29%2B40%2F%2812%2Bx%29=7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=40%2812%2Bx%29%2F%28%2812-x%29%2812%2Bx%29%29%2B40%2812-x%29%2F%28%2812%2Bx%29%2812-x%29%29=7.5 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28480%2B40x%29%2F%28144-x%5E2%29%2B%28480-40x%29%2F%28144-x%5E2%29=7.5 ALIGN=MIDDLE  ALT=\"%28480%2B40x%29%2F%28144-x%5E2%29%2B%28480-40x%29%2F%28144-x%5E2%29=7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28480%2B40x%2B480-40x%29%2F%28144-x%5E2%29=7.5 ALIGN=MIDDLE  ALT=\"%28480%2B40x%2B480-40x%29%2F%28144-x%5E2%29=7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=960%2F%28144-x%5E2%29=7.5 ALIGN=MIDDLE  ALT=\"960%2F%28144-x%5E2%29=7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=960=7.5%28144-x%5E2%29 ALIGN=MIDDLE  ALT=\"960=7.5%28144-x%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=960=1080-7.5x%5E2 ALIGN=MIDDLE  ALT=\"960=1080-7.5x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7.5x%5E2=1080-960 ALIGN=MIDDLE  ALT=\"7.5x%5E2=1080-960\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7.5x%5E2=120 ALIGN=MIDDLE  ALT=\"7.5x%5E2=120\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2=120%2F7.5 ALIGN=MIDDLE  ALT=\"x%5E2=120%2F7.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%5E2=16 ALIGN=MIDDLE  ALT=\"x%5E2=16\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Since we measured the rate of the current in the direction of the flow as a positive number,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28x=sqrt%2816%29=4%29 ALIGN=MIDDLE  ALT=\"highlight%28x=sqrt%2816%29=4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > .<BR>\n" );
document.write( "The rate of the current is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%284kph%29 ALIGN=MIDDLE  ALT=\"highlight%284kph%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > . </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );