document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=813544>Question 813544</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A car averages 80km/h to the city. On the way back it averages 120km/h. What is the average speed of the whole trip? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #489807 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=489807\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A car averages 80km/h to the city. On the way back it averages 120km/h. What is the average speed of the whole trip?<BR>\n" );
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document.write( "Find the total time for the round trip.<BR>\n" );
document.write( "d = r*t<BR>\n" );
document.write( "t = d/r<BR>\n" );
document.write( "t = d/80 + d/120<BR>\n" );
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document.write( "Total distance = 2d<BR>\n" );
document.write( "RT avg = 2d/t<BR>\n" );
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document.write( "RT avg = 2*80*120/(80 + 120)<BR>\n" );
document.write( "= 96 km/hr </SPAN>\n" );
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