document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=517775>Question 517775</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a Tour bus leaves Sacramento every Friday evening at 5 pm for a 170 mile trip.  this week however the bus leaves at 5:30 pm. to arrive on time , the driver drives 9 miles per hour faster than usual what is the buses usual speed? please show work </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #344922 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=344922\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t ALIGN=MIDDLE  ALT=\"t\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the usual driving time<BR>\n" );
document.write( "in hours to to arrive on schedule<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s ALIGN=MIDDLE  ALT=\"s\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the bus's usual speed in mi/hr<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "given:<BR>\n" );
document.write( "For the usual trip:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+s%2At+ ALIGN=MIDDLE  ALT=\"+170+=+s%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "For the late trip:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+%28+s+%2B+9+%29%2A%28+t+-+.5+%29+ ALIGN=MIDDLE  ALT=\"+170+=+%28+s+%2B+9+%29%2A%28+t+-+.5+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+s%2At+%2B+9t+-+.5s+-+4.5+ ALIGN=MIDDLE  ALT=\"+170+=+s%2At+%2B+9t+-+.5s+-+4.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Substitute (1) into (2) <BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+170+%2B+9t+-+.5s+-+4.5+ ALIGN=MIDDLE  ALT=\"+170+=+170+%2B+9t+-+.5s+-+4.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.5s+=+9t+-+4.5+ ALIGN=MIDDLE  ALT=\"+.5s+=+9t+-+4.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "also<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+170%2Ft+ ALIGN=MIDDLE  ALT=\"+s+=+170%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.5%2A%28170%2Ft%29+=+9t+-+4.5+ ALIGN=MIDDLE  ALT=\"+.5%2A%28170%2Ft%29+=+9t+-+4.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t ALIGN=MIDDLE  ALT=\"t\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+85+=+9t%5E2+-+4.5t+ ALIGN=MIDDLE  ALT=\"+85+=+9t%5E2+-+4.5t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9t%5E2+-+4.5t+-+85+=+0+ ALIGN=MIDDLE  ALT=\"9t%5E2+-+4.5t+-+85+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use quadratic equation<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+9+ ALIGN=MIDDLE  ALT=\"+a+=+9+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-4.5+ ALIGN=MIDDLE  ALT=\"+b+=+-4.5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+-85+ ALIGN=MIDDLE  ALT=\"+c+=+-85+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-%28-4.5%29+%2B-+sqrt%28+%28-4.5%29%5E2-4%2A9%2A%28-85%29+%29%29%2F%282%2A9%29+ ALIGN=MIDDLE  ALT=\"t+=+%28-%28-4.5%29+%2B-+sqrt%28+%28-4.5%29%5E2-4%2A9%2A%28-85%29+%29%29%2F%282%2A9%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28+4.5+%2B-+sqrt%28+20.25+%2B+3060+%29%29+%2F+18+ ALIGN=MIDDLE  ALT=\"t+=+%28+4.5+%2B-+sqrt%28+20.25+%2B+3060+%29%29+%2F+18+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28+4.5+%2B-+sqrt%28+3080.25+%29%29+%2F+18+ ALIGN=MIDDLE  ALT=\"t+=+%28+4.5+%2B-+sqrt%28+3080.25+%29%29+%2F+18+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28++4.5+%2B+55.5+%29+%2F+18+ ALIGN=MIDDLE  ALT=\"+t+=+%28++4.5+%2B+55.5+%29+%2F+18+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+60%2F18+ ALIGN=MIDDLE  ALT=\"+t+=+60%2F18+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+10%2F3+ ALIGN=MIDDLE  ALT=\"+t+=+10%2F3+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "and, from (1)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+170%2Ft+ ALIGN=MIDDLE  ALT=\"+s+=+170%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+170%2A%283%2F10%29+ ALIGN=MIDDLE  ALT=\"+s+=+170%2A%283%2F10%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+51+ ALIGN=MIDDLE  ALT=\"+s+=+51+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The usual speed is 51 mi/hr<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+%28+s+%2B+9+%29%2A%28+t+-+.5+%29+ ALIGN=MIDDLE  ALT=\"+170+=+%28+s+%2B+9+%29%2A%28+t+-+.5+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+%28+51+%2B+9+%29%2A%28+20%2F6+-+3%2F6+%29+ ALIGN=MIDDLE  ALT=\"+170+=+%28+51+%2B+9+%29%2A%28+20%2F6+-+3%2F6+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+60%2A%28+17%2F6+%29+ ALIGN=MIDDLE  ALT=\"+170+=+60%2A%28+17%2F6+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+60%2A%2817%2F6%29+ ALIGN=MIDDLE  ALT=\"+170+=+60%2A%2817%2F6%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+170+=+170+ ALIGN=MIDDLE  ALT=\"+170+=+170+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );