document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1032342>Question 1032342</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A train leaves Philadelphia at 1:00 PM. A second train leaves the same city in the same direction at 3:00 PM. The second train travels 20 mph faster than the first. If the second train overtakes the first at 9:00 PM, what is the speed of each of the two trains? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #646964 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=646964\">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+ ALIGN=MIDDLE  ALT=\"+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the 1st train in mi/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+%2B+20+ ALIGN=MIDDLE  ALT=\"+s+%2B+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the 2nd train in mi/hr<BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "What is the 1st train's head start in miles?<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d%5B1%5D+=+s%2A2+ ALIGN=MIDDLE  ALT=\"+d%5B1%5D+=+s%2A2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Start a stopwatch when the 2nd train leaves<BR>\n" );
document.write( "at 3 PM and stop the stopwatch at 9 PM<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+ ALIGN=MIDDLE  ALT=\"+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = distance in miles the 2nd train<BR>\n" );
document.write( "travels until it catches up with 1st train at 9 PM<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Equation for 1st train:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+-+2s+=+s%2A6+ ALIGN=MIDDLE  ALT=\"+d+-+2s+=+s%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for 2nd train:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d=+%28+s%2B20+%29%2A6+ ALIGN=MIDDLE  ALT=\"+d=+%28+s%2B20+%29%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------------<BR>\n" );
document.write( "Substitute (2) into (1)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+s%2B20+%29%2A6+-+2s+=+s%2A6+ ALIGN=MIDDLE  ALT=\"+%28+s%2B20+%29%2A6+-+2s+=+s%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+6s+%2B+120+-+2s+=+6s+ ALIGN=MIDDLE  ALT=\"+6s+%2B+120+-+2s+=+6s+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2s+=+120+ ALIGN=MIDDLE  ALT=\"+2s+=+120+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+60+ ALIGN=MIDDLE  ALT=\"+s+=+60+\"   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+%2B+20+=+80+ ALIGN=MIDDLE  ALT=\"+s+%2B+20+=+80+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The 1st train's speed is 60 mi/hr<BR>\n" );
document.write( "The 2nd train's speed is 80 mi/hr<BR>\n" );
document.write( "------------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+-+2s+=+s%2A6+ ALIGN=MIDDLE  ALT=\"+d+-+2s+=+s%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+-+2%2A60+=+6%2A60+ ALIGN=MIDDLE  ALT=\"+d+-+2%2A60+=+6%2A60+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+-+120+=+360+ ALIGN=MIDDLE  ALT=\"+d+-+120+=+360+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+480+ ALIGN=MIDDLE  ALT=\"+d+=+480+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+%28+s%2B20+%29%2A6+ ALIGN=MIDDLE  ALT=\"+d+=+%28+s%2B20+%29%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+%28+60%2B20+%29%2A6+ ALIGN=MIDDLE  ALT=\"+d+=+%28+60%2B20+%29%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+80%2A6+ ALIGN=MIDDLE  ALT=\"+d+=+80%2A6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+480+ ALIGN=MIDDLE  ALT=\"+d+=+480+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );