document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=299899>Question 299899</A>: <I><SPAN STYLE=\"word-break: break-all;\"> an express train travels 299 mi. between two cities. during the first 111 mi. of a trip, the train traveled through mountainous terrain. the train traveled 10 mi. per hour slower through mountainous terrain then through level terrain. if the total time to travel between two cities was 7 hours, find the speed of the train on level terrain </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #215349 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=215349\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> An express train travels 299 mi. between two cities.<BR>\n" );
document.write( " during the first 111 mi. of a trip, the train traveled through mountainous terrain.<BR>\n" );
document.write( " the train traveled 10 mi. per hour slower through mountainous terrain then through level terrain.<BR>\n" );
document.write( " if the total time to travel between two cities was 7 hours, find the speed of the train on level terrain<BR>\n" );
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document.write( "Let s = train speed thru level terrain<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s-10) = speed thru the mountains<BR>\n" );
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document.write( "299 - 111 = 188 mi, dist thru level terrain<BR>\n" );
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document.write( "Write time equation: Time = dist/speed<BR>\n" );
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document.write( "Time in mts + time on level ground = 7 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=111%2F%28%28s-10%29%29 ALIGN=MIDDLE  ALT=\"111%2F%28%28s-10%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=188%2Fs ALIGN=MIDDLE  ALT=\"188%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 7 <BR>\n" );
document.write( "multiply by s(s-10), results:<BR>\n" );
document.write( "111s + 188(s-10) = 7s(s-10) <BR>\n" );
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document.write( "111s + 188s - 1880 = 7s^2 - 70s<BR>\n" );
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document.write( "299s - 1880 = 7s^2 - 70s<BR>\n" );
document.write( "Arrange as a quadratic on the right<BR>\n" );
document.write( "0 = 7s^2 - 70s - 299s + 1880 <BR>\n" );
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document.write( "7s^2 - 369s + 1880 = 0<BR>\n" );
document.write( "You can use the quadratic formula here but this will Factor to: <BR>\n" );
document.write( "(7s - 40)(s - 47) = 0<BR>\n" );
document.write( "The reasonable solution:<BR>\n" );
document.write( "s = 47 mph on level terrain<BR>\n" );
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document.write( "Check solution by finding the times<BR>\n" );
document.write( "111/37 = 3 hrs<BR>\n" );
document.write( "188/47 = 4 hrs<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "total = 7 hr <BR>\n" );
document.write( " </SPAN>\n" );
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