document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=980585>Question 980585</A>: <I><SPAN STYLE=\"word-break: break-all;\"> `A train goes from New Orleans to Boston at 40 mph. On the way back it returns with a speed of 80 miles per hour. If it takes one hour less time to return, what is it's average speed? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #601713 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=601713\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Average speed is always [ total distance ] / [ total time ]<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+ ALIGN=MIDDLE  ALT=\"+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = distance in miles between New Orleans and Boston<BR>\n" );
document.write( "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;\" > = time in hrs going from New Orleans to Boston<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+-+1+ ALIGN=MIDDLE  ALT=\"+t+-+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = time in hrs going from Boston to New Orleans<BR>\n" );
document.write( "-----------------------------------------------------<BR>\n" );
document.write( "Equation for New Orleans to Boston:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+40t+ ALIGN=MIDDLE  ALT=\"+d+=+40t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for Boston to New Orleans:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+80%2A%28+t-1+%29+ ALIGN=MIDDLE  ALT=\"+d+=+80%2A%28+t-1+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "[ total distance ] = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2d+ ALIGN=MIDDLE  ALT=\"+2d+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "--------------------------------------<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+d%2F40+ ALIGN=MIDDLE  ALT=\"+t+=+d%2F40+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+80%2A%28+t-1%29+ ALIGN=MIDDLE  ALT=\"+d+=+80%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=+t-1+=+d%2F80+ ALIGN=MIDDLE  ALT=\"+t-1+=+d%2F80+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "---------------------------------<BR>\n" );
document.write( "[ total time ] = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+t-1+=+d%2F40+%2B+d%2F80+ ALIGN=MIDDLE  ALT=\"+t+%2B+t-1+=+d%2F40+%2B+d%2F80+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "[ total distance ] / [ total time ] = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+2d+%29+%2F+%28+d%2F40+%2B+d%2F80+%29+ ALIGN=MIDDLE  ALT=\"+%28+2d+%29+%2F+%28+d%2F40+%2B+d%2F80+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "Divide top and bottom by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+ ALIGN=MIDDLE  ALT=\"+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2+%2F+%28+1%2F40+%2B+1%2F80+%29+ ALIGN=MIDDLE  ALT=\"+2+%2F+%28+1%2F40+%2B+1%2F80+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply top and bottom by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+80+ ALIGN=MIDDLE  ALT=\"+80+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+160+%2F+%28+2+%2B+1+%29+=+53.333+ ALIGN=MIDDLE  ALT=\"+160+%2F+%28+2+%2B+1+%29+=+53.333+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "--------------------------------<BR>\n" );
document.write( "Note that you do not take the average of the two averages<BR>\n" );
document.write( "which would be: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+40+%2B+80+%29+%2F+2+=+60+ ALIGN=MIDDLE  ALT=\"+%28+40+%2B+80+%29+%2F+2+=+60+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );