document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=697811>Question 697811</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Jacob travelled 225 km to deliver goods from a factory. Had he travelled 15 kph more, he could make the trip in 1 ¼ hours less time and could have gone back to the factory earlier than usual. What is Jacob’s usual speed? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #430404 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=430404\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  Jacob traveled 225 km to deliver goods from a factory.<BR>\n" );
document.write( " Had he traveled 15 kph more, he could make the trip in 1 ¼ hours less time and could have gone back to the factory earlier than usual.<BR>\n" );
document.write( " What is Jacob’s usual speed?<BR>\n" );
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document.write( "Let s = his usual speed<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s+15) = 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( "Normal time - Faster time = 1.25 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=225%2Fs ALIGN=MIDDLE  ALT=\"225%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=225%2F%28%28s%2B15%29%29 ALIGN=MIDDLE  ALT=\"225%2F%28%28s%2B15%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1.25<BR>\n" );
document.write( "Multiply by s(s+15),resulting in:<BR>\n" );
document.write( "225(s+15)- 225s = 1.25s(s+15)<BR>\n" );
document.write( "225s + 3375 - 225s = 1.25s^2 + 18.75s<BR>\n" );
document.write( "A quadratic equation<BR>\n" );
document.write( "1.25s^2 + 18.75s - 3375 = 0<BR>\n" );
document.write( "multiplying by 4 gets rid of the decimals, we have<BR>\n" );
document.write( "5s^2 + 75s - 13500 = 0<BR>\n" );
document.write( "now we can simplify this, divide by 5<BR>\n" );
document.write( "s^2 + 15s - 2700 = 0<BR>\n" );
document.write( "Factors to<BR>\n" );
document.write( "(s-45)(s+60) = 0<BR>\n" );
document.write( "the positive solution<BR>\n" );
document.write( "s = 45 km/h is his usual speed<BR>\n" );
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document.write( "Confirm this by finding the time at each speed<BR>\n" );
document.write( "225/45 = 5 hrs<BR>\n" );
document.write( "225.60 = 3.75 hrs<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "time dif:1.25 hrs </SPAN>\n" );
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