document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=126593>Question 126593</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Two trains leave a city at the same time. One travels north, and the other travels south 20 mph faster. In 2hr, the trains are 280 mi apart, find their speeds. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #92740 by </B><A HREF=/tutors/aboutme.mpl?userid=marcsam823><B>marcsam823(57)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=marcsam823><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=92740\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For this problem you'll need to remember that rate x time = distance or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2At+=+d ALIGN=MIDDLE  ALT=\"r%2At+=+d\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "We know that both trains travelled a distance that separated them by 280 miles after 2 hours. Therefore:\r<BR>\n" );
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document.write( "--The distance travelled by the northbound train (x) plus the distance travelled by the southbound train (y) totals 280 miles or, algebraically:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+%2B+y+=+280 ALIGN=MIDDLE  ALT=\"x+%2B+y+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "1. Using our formula <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2At+=+d ALIGN=MIDDLE  ALT=\"r%2At+=+d\"   DISABLED_style= \"max-width:90%; height:auto;\" > we can substitute:<BR>\n" );
document.write( "a. Let r = the speed of the northbound train <BR>\n" );
document.write( "b. Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+%2B+20 ALIGN=MIDDLE  ALT=\"r+%2B+20\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the southbound train (20 mph faster)<BR>\n" );
document.write( "c. Both trains have travelled for 2 hours:<BR>\n" );
document.write( "d. Let x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2Ar ALIGN=MIDDLE  ALT=\"2%2Ar\"   DISABLED_style= \"max-width:90%; height:auto;\" >  <BR>\n" );
document.write( "e. Let y = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2A%28r+%2B+20%29 ALIGN=MIDDLE  ALT=\"2%2A%28r+%2B+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
document.write( "\n" );
document.write( "2. Substitute for x and y and solve for r:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2r+%2B+2%28r%2B20%29+=+280 ALIGN=MIDDLE  ALT=\"2r+%2B+2%28r%2B20%29+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2r+%2B+2r+%2B+40+=+280 ALIGN=MIDDLE  ALT=\"2r+%2B+2r+%2B+40+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4r+=+240 ALIGN=MIDDLE  ALT=\"4r+=+240\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+60 ALIGN=MIDDLE  ALT=\"r+=+60\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+%2B+20+=+80 ALIGN=MIDDLE  ALT=\"r+%2B+20+=+80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-The northbound train travels at 60 mph<BR>\n" );
document.write( "-The southbound train travels at 80 mph (20 mph faster)\r<BR>\n" );
document.write( "\n" );
document.write( "3. Check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2r+%2B+2%28r+%2B+20%29+=+280 ALIGN=MIDDLE  ALT=\"2r+%2B+2%28r+%2B+20%29+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2860%29+%2B+2%28%2860%29+%2B+20%29+=+280 ALIGN=MIDDLE  ALT=\"2%2860%29+%2B+2%28%2860%29+%2B+20%29+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120+%2B+2%2880%29+=+280 ALIGN=MIDDLE  ALT=\"120+%2B+2%2880%29+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120+%2B+160+=+280 ALIGN=MIDDLE  ALT=\"120+%2B+160+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=280+=+280 ALIGN=MIDDLE  ALT=\"280+=+280\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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