document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=736876>Question 736876</A>: <I><SPAN STYLE=\"word-break: break-all;\"> John drives along a straight motorway at a constant speed for 120km.  Next day he completes the same journey travelling 10km/h faster.  He completes this journey in 10 mins less than the first journey.  find the 2 speeds at which he travelled.\r<BR>\n" );
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document.write( "Please help!I know d=s x t.<BR>\n" );
document.write( "120=t x s<BR>\n" );
document.write( "120= t-10 x s + 10.\r<BR>\n" );
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document.write( "Have come up with various answers- none of them right!  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #450055 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=450055\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  John drives along a straight motorway at a constant speed for 120km.<BR>\n" );
document.write( " Next day he completes the same journey travelling 10km/h faster.<BR>\n" );
document.write( " He completes this journey in 10 mins less than the first journey.<BR>\n" );
document.write( " find the 2 speeds at which he travelled. <BR>\n" );
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document.write( "let s = his first speed<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s+10) = his faster speed<BR>\n" );
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document.write( "change 10 min to 1/6 hr<BR>\n" );
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document.write( "Write a time equation, time = dist/speed:<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120%2Fs ALIGN=MIDDLE  ALT=\"120%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120%2F%28%28s%2B10%29%29 ALIGN=MIDDLE  ALT=\"120%2F%28%28s%2B10%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F6 ALIGN=MIDDLE  ALT=\"1%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "multiply by 6s(s+10) to clear the denominators, resulting in:<BR>\n" );
document.write( "6(s+10)*120 - 6s(120) = s(s+10)<BR>\n" );
document.write( "120(6s+60) - 720s = s^2 + 10s<BR>\n" );
document.write( "720s + 7200 - 720s = s^2 + 10s<BR>\n" );
document.write( "a quadratic equation<BR>\n" );
document.write( "0 = s^2 + 10s - 7200 = 0<BR>\n" );
document.write( "Factors to<BR>\n" );
document.write( "(s+90)(s-80) = 0<BR>\n" );
document.write( "the positive solution all we want here<BR>\n" );
document.write( "s = 80 km/hr and 90 km/hr are the two speeds<BR>\n" );
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