document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=260225>Question 260225</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A car travels 120 miles from A to B at 30 miles per hour but returns the same distance at 40 miles per hour.  What is the average speed for the round trip?   </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #191666 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=191666\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A car travels 120 miles from A to B at 30 miles per hour but returns the same distance at 40 miles per hour. What is the average speed for the round trip? <BR>\n" );
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document.write( "120 miles at 30 mph takes 4 hours<BR>\n" );
document.write( "120 miles at 40 mph takes 3 hours<BR>\n" );
document.write( "A total of 240 miles in 7 hours<BR>\n" );
document.write( "--> 240/7 =~ 34.2857<BR>\n" );
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document.write( "If you drive an hour at 40 and an hour at 30, the average speed is 35.<BR>\n" );
document.write( "  It's never the average of the 2 speeds when the distance is the same. It's always less, because more time is spent at 30 mph than at 40 mph.<BR>\n" );
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document.write( "This is the basis of the Michelson-Morley experiment that disproved the existence of \"the ether.\"<BR>\n" );
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