document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=323778>Question 323778</A>: <I><SPAN STYLE=\"word-break: break-all;\"> David and Keith are route drivers for a fast -photo company. David route is 80 miles, and Keith’s is 100 miles. Keith averages 10 mph more than David and finishes his route 10 minutes before David. What is David’s speed.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #231740 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=231740\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Equation for David:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+r%2At ALIGN=MIDDLE  ALT=\"d+=+r%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=80+=+r%2At ALIGN=MIDDLE  ALT=\"80+=+r%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for Keith:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+%28r+%2B+10%29%2A%28t+-+1%2F6%29 ALIGN=MIDDLE  ALT=\"100+=+%28r+%2B+10%29%2A%28t+-+1%2F6%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+rt+%2B+10t+-+%281%2F6%29%2Ar+-+10%2F6 ALIGN=MIDDLE  ALT=\"100+=+rt+%2B+10t+-+%281%2F6%29%2Ar+-+10%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "By substitution:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+80+%2B+10t+-+%281%2F6%29%2A%2880%2Ft%29+-+10%2F6 ALIGN=MIDDLE  ALT=\"100+=+80+%2B+10t+-+%281%2F6%29%2A%2880%2Ft%29+-+10%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+=+10t+-+%2840%2F%283t%29+-+5%2F3%29 ALIGN=MIDDLE  ALT=\"20+=+10t+-+%2840%2F%283t%29+-+5%2F3%29\"   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=3t ALIGN=MIDDLE  ALT=\"3t\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=60t+=+30t%5E2+-+40+-+5t ALIGN=MIDDLE  ALT=\"60t+=+30t%5E2+-+40+-+5t\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30t%5E2+-+65t+-+40+=+0 ALIGN=MIDDLE  ALT=\"30t%5E2+-+65t+-+40+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6t%5E2+-+13t+-+8+=+0 ALIGN=MIDDLE  ALT=\"6t%5E2+-+13t+-+8+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use the quadratic formula<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+=+6 ALIGN=MIDDLE  ALT=\"a+=+6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+-13 ALIGN=MIDDLE  ALT=\"b+=+-13\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c+=+-8 ALIGN=MIDDLE  ALT=\"c+=+-8\"   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-%28-13%29+%2B-+sqrt%28+%28-13%29%5E2-4%2A6%2A%28-8%29+%29%29%2F%282%2A6%29+ ALIGN=MIDDLE  ALT=\"t+=+%28-%28-13%29+%2B-+sqrt%28+%28-13%29%5E2-4%2A6%2A%28-8%29+%29%29%2F%282%2A6%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+13+%2B-+sqrt%28++169+%2B+192+%29%29%2F12+ ALIGN=MIDDLE  ALT=\"t+=+%28+13+%2B-+sqrt%28++169+%2B+192+%29%29%2F12+\"   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+13+%2B-+sqrt%28++361+%29%29%2F12+ ALIGN=MIDDLE  ALT=\"t+=+%28+13+%2B-+sqrt%28++361+%29%29%2F12+\"   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+13+%2B-+19%29%2F12+ ALIGN=MIDDLE  ALT=\"t+=+%28+13+%2B-+19%29%2F12+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+32%2F12 ALIGN=MIDDLE  ALT=\"t+=+32%2F12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+8%2F3 ALIGN=MIDDLE  ALT=\"t+=+8%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "For David:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=80+=+r%2At ALIGN=MIDDLE  ALT=\"80+=+r%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+80%2F%288%2F3%29 ALIGN=MIDDLE  ALT=\"r+=+80%2F%288%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+240%2F8 ALIGN=MIDDLE  ALT=\"r+=+240%2F8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+30 ALIGN=MIDDLE  ALT=\"r+=+30\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "David's speed is 30 mi/hr<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "For Keith<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+%28r+%2B+10%29%2A%28t+-+1%2F6%29 ALIGN=MIDDLE  ALT=\"100+=+%28r+%2B+10%29%2A%28t+-+1%2F6%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+%2830+%2B+10%29%2A%288%2F3+-+1%2F6%29 ALIGN=MIDDLE  ALT=\"100+=+%2830+%2B+10%29%2A%288%2F3+-+1%2F6%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+40%2A%2816%2F6+-+1%2F6%29 ALIGN=MIDDLE  ALT=\"100+=+40%2A%2816%2F6+-+1%2F6%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=100+=+40%2A%2815%2F6%29 ALIGN=MIDDLE  ALT=\"100+=+40%2A%2815%2F6%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=600+=+40%2A15 ALIGN=MIDDLE  ALT=\"600+=+40%2A15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=600+=+600 ALIGN=MIDDLE  ALT=\"600+=+600\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );