document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=957374>Question 957374</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An express train travels 380 miles between two cities. During the first 120 miles of a trip, the train traveled through mountainous terrain. The train traveled 12 miles per hour slower through mountainous terrain than through level terrain. If the total time to travel between the cities was 8 hours, find the speed of the train on level terrain.\r<BR>\n" );
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document.write( "Can't seem to solve this one </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #585049 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=585049\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+d%2Fr+ ALIGN=MIDDLE  ALT=\"+t+=+d%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "---------------<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+ ALIGN=MIDDLE  ALT=\"+r+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the train's rate in mi/hr on level terrain<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+-+12+ ALIGN=MIDDLE  ALT=\"+r+-+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the train's rate in mi/hr in mountainous terrain<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the train's time in hrs on mountainous terrain<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+ ALIGN=MIDDLE  ALT=\"+8+-+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the train's time on level terrain<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "For mountainous terrain:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+120+%2F+%28+r+-+12+%29+ ALIGN=MIDDLE  ALT=\"+t+=+120+%2F+%28+r+-+12+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "For level terrain:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+=+%28+380+-+120+%29+%2F+r+ ALIGN=MIDDLE  ALT=\"+8+-+t+=+%28+380+-+120+%29+%2F+r+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+=+260%2Fr+ ALIGN=MIDDLE  ALT=\"+8+-+t+=+260%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+8+-+260%2Fr+ ALIGN=MIDDLE  ALT=\"+t+=+8+-+260%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "By substitution:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+120%2F%28+r-12+%29+=+8+-+260%2Fr+ ALIGN=MIDDLE  ALT=\"+120%2F%28+r-12+%29+=+8+-+260%2Fr+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r%2A%28+r-12+%29+ ALIGN=MIDDLE  ALT=\"+r%2A%28+r-12+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+120r+=+8%2Ar%2A%28+r-12+%29+-+260%2A%28+r-12+%29+ ALIGN=MIDDLE  ALT=\"+120r+=+8%2Ar%2A%28+r-12+%29+-+260%2A%28+r-12+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+120r+=+8r%5E2+-+96r+-+260r+%2B+3120+ ALIGN=MIDDLE  ALT=\"+120r+=+8r%5E2+-+96r+-+260r+%2B+3120+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8r%5E2+-+476r+%2B+3120+=+0+ ALIGN=MIDDLE  ALT=\"+8r%5E2+-+476r+%2B+3120+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2r%5E2+-+119r+%2B+780+=+0+ ALIGN=MIDDLE  ALT=\"+2r%5E2+-+119r+%2B+780+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "Use quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+r+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+2+ ALIGN=MIDDLE  ALT=\"+a+=+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-119+ ALIGN=MIDDLE  ALT=\"+b+=+-119+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+780+ ALIGN=MIDDLE  ALT=\"+c+=+780+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28-%28-119%29+%2B-+sqrt%28+%28-119%29%5E2+-+4%2A2%2A780+%29%29+%2F+%282%2A2%29+ ALIGN=MIDDLE  ALT=\"+r+=+%28-%28-119%29+%2B-+sqrt%28+%28-119%29%5E2+-+4%2A2%2A780+%29%29+%2F+%282%2A2%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+119+%2B-+sqrt%28+14161+-+6240+%29%29+%2F+4+ ALIGN=MIDDLE  ALT=\"+r+=+%28+119+%2B-+sqrt%28+14161+-+6240+%29%29+%2F+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+119+%2B-+sqrt%28+7921+%29%29+%2F+4+ ALIGN=MIDDLE  ALT=\"+r+=+%28+119+%2B-+sqrt%28+7921+%29%29+%2F+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+119+-+89+%29+%2F+4+ ALIGN=MIDDLE  ALT=\"+r+=+%28+119+-+89+%29+%2F+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+30%2F4+ ALIGN=MIDDLE  ALT=\"+r+=+30%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+7.5+ ALIGN=MIDDLE  ALT=\"+r+=+7.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "This can't be the answer, since I have to subtract <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+12+ ALIGN=MIDDLE  ALT=\"+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "to get rate on mountainous terrain, so<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+%28+119+%2B+89+%29+%2F+4+ ALIGN=MIDDLE  ALT=\"+r+=+%28+119+%2B+89+%29+%2F+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+208%2F4+ ALIGN=MIDDLE  ALT=\"+r+=+208%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+=+52+ ALIGN=MIDDLE  ALT=\"+r+=+52+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+r+-+12+=+40+ ALIGN=MIDDLE  ALT=\"+r+-+12+=+40+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "The speed on level terrain is 52 km/hr<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+120+%2F+%28+r+-+12+%29+ ALIGN=MIDDLE  ALT=\"+t+=+120+%2F+%28+r+-+12+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+120+%2F+%28+52+-+12+%29+ ALIGN=MIDDLE  ALT=\"+t+=+120+%2F+%28+52+-+12+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+120%2F40+ ALIGN=MIDDLE  ALT=\"+t+=+120%2F40+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+3+ ALIGN=MIDDLE  ALT=\"+t+=+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+=+%28+380+-+120+%29+%2F+r+ ALIGN=MIDDLE  ALT=\"+8+-+t+=+%28+380+-+120+%29+%2F+r+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+=+260+%2F+52+ ALIGN=MIDDLE  ALT=\"+8+-+t+=+260+%2F+52+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+-+t+=+5+ ALIGN=MIDDLE  ALT=\"+8+-+t+=+5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+3+ ALIGN=MIDDLE  ALT=\"+t+=+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "OK<BR>\n" );
document.write( "Hope I got it!\r<BR>\n" );
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document.write( "  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );