document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1072760>Question 1072760</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Tracy and Kelly are running laps on the indoor track — at steady speeds, but in opposite directions. They meet every 20 seconds. It takes Tracy 45 seconds to complete each lap. How many seconds does it take for each of Kelly’s laps? (Answer must be checked as well) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #687618 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=687618\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = Tracy's speed in laps / sec<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B2%5D+ ALIGN=MIDDLE  ALT=\"+s%5B2%5D+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = Kelly's speed in laps / sec<BR>\n" );
document.write( "---------------------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+=+1%2F45+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+=+1%2F45+\"   DISABLED_style= \"max-width:90%; height:auto;\" > laps/sec<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+ ALIGN=MIDDLE  ALT=\"+x+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the fraction of a lap that That Tracy<BR>\n" );
document.write( "covers in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+20+ ALIGN=MIDDLE  ALT=\"+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+-+x+ ALIGN=MIDDLE  ALT=\"+1+-+x+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the fraction of a lap that Kelly covers<BR>\n" );
document.write( "in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+20+ ALIGN=MIDDLE  ALT=\"+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "----------------------<BR>\n" );
document.write( "Tracy's speed is:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+=+x%2F20+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+=+x%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F45+=+x%2F20+ ALIGN=MIDDLE  ALT=\"+1%2F45+=+x%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+4%2F9+ ALIGN=MIDDLE  ALT=\"+x+=+4%2F9+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "And Kelly's speed is:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+1+-+x+%29%2F20+=+%28+1+-+4%2F9+%29+%2F+20+ ALIGN=MIDDLE  ALT=\"+%28+1+-+x+%29%2F20+=+%28+1+-+4%2F9+%29+%2F+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+5%2F9+%29%2F20+=+1%2F36+ ALIGN=MIDDLE  ALT=\"+%28+5%2F9+%29%2F20+=+1%2F36+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So Kelly completes 1 lap in 36sec<BR>\n" );
document.write( "------------------------------------<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+=+x%2F20+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+=+x%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+=+%284%2F9%29%2F20+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+=+%284%2F9%29%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B1%5D+=+1%2F45+ ALIGN=MIDDLE  ALT=\"+s%5B1%5D+=+1%2F45+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5B2%5D+=+1%2F36+ ALIGN=MIDDLE  ALT=\"+s%5B2%5D+=+1%2F36+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "Think of one of them standing still and the other<BR>\n" );
document.write( "moving at the sum of their speeds<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+=+%28+1%2F45+%2B+1%2F36+%29%2A20+ ALIGN=MIDDLE  ALT=\"+1+=+%28+1%2F45+%2B+1%2F36+%29%2A20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+=+%28+4%2F180+%2B+5%2F180+%29%2A20+ ALIGN=MIDDLE  ALT=\"+1+=+%28+4%2F180+%2B+5%2F180+%29%2A20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+=+%28+9%2F180+%29%2A20+ ALIGN=MIDDLE  ALT=\"+1+=+%28+9%2F180+%29%2A20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+=+%281%2F20%29%2A20+ ALIGN=MIDDLE  ALT=\"+1+=+%281%2F20%29%2A20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1+=+1+ ALIGN=MIDDLE  ALT=\"+1+=+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "( 1 lap finished in 20 sec )<BR>\n" );
document.write( "OK\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );