document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1010050>Question 1010050</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A bus trip of 90 miles would have taken an hour less if the average speed had been increased by 3 miles per hour. Find the usual average speed of the bus.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #625530 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=625530\">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=+s+ ALIGN=MIDDLE  ALT=\"+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the average speed of the bus<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+90+=+s%2At+ ALIGN=MIDDLE  ALT=\"+90+=+s%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+90+=+%28+s+%2B+3+%29%2A%28+t+-+1+%29+ ALIGN=MIDDLE  ALT=\"+90+=+%28+s+%2B+3+%29%2A%28+t+-+1+%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=+90+=+t%2A%28+s+%2B+3+%29+-+s+-+3+ ALIGN=MIDDLE  ALT=\"+90+=+t%2A%28+s+%2B+3+%29+-+s+-+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+90%2Fs+ ALIGN=MIDDLE  ALT=\"+t+=+90%2Fs+\"   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=+90+=+%28+90%2Fs+%29%2A%28+s+%2B+3+%29+-+s+-+3+ ALIGN=MIDDLE  ALT=\"+90+=+%28+90%2Fs+%29%2A%28+s+%2B+3+%29+-+s+-+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+93+=+%28+90%2Fs+%29%2A%28+s+%2B+3+%29+-+s+ ALIGN=MIDDLE  ALT=\"+93+=+%28+90%2Fs+%29%2A%28+s+%2B+3+%29+-+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+93+=+90+%2B+270%2Fs+-+s+ ALIGN=MIDDLE  ALT=\"+93+=+90+%2B+270%2Fs+-+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3+=+270%2Fs+-+s%0D%0AMultiply+both+sides+by+%7B%7B%7B+s+ ALIGN=MIDDLE  ALT=\"+3+=+270%2Fs+-+s%0D%0AMultiply+both+sides+by+%7B%7B%7B+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3s+=+270+-+s%5E2+ ALIGN=MIDDLE  ALT=\"+3s+=+270+-+s%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%5E2+%2B+3s+-+270+=+0+ ALIGN=MIDDLE  ALT=\"+s%5E2+%2B+3s+-+270+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+s+=+%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+=+1+ ALIGN=MIDDLE  ALT=\"+a+=+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+3+ ALIGN=MIDDLE  ALT=\"+b+=+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+-270+ ALIGN=MIDDLE  ALT=\"+c+=+-270+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+%28-3+%2B-+sqrt%28+3%5E2+-+4%2A1%2A%28-270%29+%29%29+%2F+%282%2A1%29+ ALIGN=MIDDLE  ALT=\"+s+=+%28-3+%2B-+sqrt%28+3%5E2+-+4%2A1%2A%28-270%29+%29%29+%2F+%282%2A1%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+%28-3+%2B-+sqrt%28+9+%2B+1080+%29%29+%2F2+ ALIGN=MIDDLE  ALT=\"+s+=+%28-3+%2B-+sqrt%28+9+%2B+1080+%29%29+%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+%28-3+%2B+33+%29+%2F2+ ALIGN=MIDDLE  ALT=\"+s+=+%28-3+%2B+33+%29+%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" >  <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+30%2F2+ ALIGN=MIDDLE  ALT=\"+s+=+30%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+15+ ALIGN=MIDDLE  ALT=\"+s+=+15+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The usual speed is 15 mi/hr<BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+90%2Fs+ ALIGN=MIDDLE  ALT=\"+t+=+90%2Fs+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+90%2F15+ ALIGN=MIDDLE  ALT=\"+t+=+90%2F15+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+6+ ALIGN=MIDDLE  ALT=\"+t+=+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+90+=+%28+s+%2B+3+%29%2A%28+t+-+1+%29+ ALIGN=MIDDLE  ALT=\"+90+=+%28+s+%2B+3+%29%2A%28+t+-+1+%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=+90+=+%28+15+%2B+3+%29%2A%28+t+-+1+%29+ ALIGN=MIDDLE  ALT=\"+90+=+%28+15+%2B+3+%29%2A%28+t+-+1+%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=+90+=+18t+-+18+ ALIGN=MIDDLE  ALT=\"+90+=+18t+-+18+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+18t+=+108+ ALIGN=MIDDLE  ALT=\"+18t+=+108+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+6+ ALIGN=MIDDLE  ALT=\"+t+=+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );