document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=688467>Question 688467</A>: <I><SPAN STYLE=\"word-break: break-all;\"> When the speed of a train is increased by 10 mph, it can cover a 300 mile route in one hour less time.  What is the original speed of the train? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #425638 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=425638\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> When the speed of a train is increased by 10 mph, it can cover a 300 mile route in one hour less time.<BR>\n" );
document.write( " What is the original speed of the train?<BR>\n" );
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document.write( "Let s = the original speed of the train<BR>\n" );
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document.write( "Write a time equation, time = dist/speed<BR>\n" );
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document.write( "Original time - faster time = 1 hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=300%2Fs ALIGN=MIDDLE  ALT=\"300%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=300%2F%28%28s%2B10%29%29 ALIGN=MIDDLE  ALT=\"300%2F%28%28s%2B10%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1<BR>\n" );
document.write( "Multiply by s(s+10), this clears the denominators, resulting in:<BR>\n" );
document.write( "300(s+10) - 300s = s(s+10)<BR>\n" );
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document.write( "300s + 3000 - 300s = s^2 + 10s<BR>\n" );
document.write( "A quadratic equation<BR>\n" );
document.write( "0 = s^2 + 10s - 3000 <BR>\n" );
document.write( "This factors to<BR>\n" );
document.write( "(s+60(s-50) = 0<BR>\n" );
document.write( "the positive solution is what we want here<BR>\n" );
document.write( "s = 50 mph is the original speed<BR>\n" );
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document.write( "Confirm this find the time of each scenario<BR>\n" );
document.write( "300/50 = 6 hrs<BR>\n" );
document.write( "300/60 = 5 hrs, 1 hr less </SPAN>\n" );
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