document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=621132>Question 621132</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If a car had increased its average speed for a 210 mile journey by 5 MPH the journey would have been completed in one hour less.  What was the original speed of the car for the journey? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #390598 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=390598\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If a car had increased its average speed for a 210 mile journey by 5 MPH the journey would have been completed in one hour less.<BR>\n" );
document.write( " What was the original speed of the car for the journey?<BR>\n" );
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document.write( "Let s = original speed<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s+5) = the faster speed<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=210%2Fs ALIGN=MIDDLE  ALT=\"210%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=210%2F%28%28s%2B5%29%29 ALIGN=MIDDLE  ALT=\"210%2F%28%28s%2B5%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1<BR>\n" );
document.write( "multiply equation by s(s+5); results:<BR>\n" );
document.write( "210(s+5) - 210s = 1s(s+5)<BR>\n" );
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document.write( "210s + 1050 - 210s = s^2 + 5s<BR>\n" );
document.write( "Arrange as a quadratic equation<BR>\n" );
document.write( "s^2 + 5s - 1050 = 0<BR>\n" );
document.write( "You can use the quadratic equation, but this will factor<BR>\n" );
document.write( "(s-30)(s+35) = 0<BR>\n" );
document.write( "the positive solution is all we want here<BR>\n" );
document.write( "s = 30 mph is the original speed<BR>\n" );
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document.write( "Check this out; find the actual time for each speed<BR>\n" );
document.write( "210/30 = 7 hr<BR>\n" );
document.write( "210/35 = 6 hrs<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "differ: 1 hr </SPAN>\n" );
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