document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=867796>Question 867796</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A jet flies from New York to Atlanta at an average rate of 420 mph.  On the return trip, there is a strong tail-wind and the plane's speed is 630 mph.  What is the average 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 #523233 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=523233\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's say that the distance from New York to Atlanta is 420 miles. This is not true, but for the sake of the problem, let's say it is. \r<BR>\n" );
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document.write( "The speed going from New York to Atlanta is 420 mph. So it will take t = D/r = 420/420 = 1 hour for the plane to get there.\r<BR>\n" );
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document.write( "Coming back the same distance, it is now going 630 mph. So it will take t = D/r = 420/630 = 2/3 an hour to get back\r<BR>\n" );
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document.write( "Overall, the plane has traveled for 1+2/3 = 3/3+2/3 = 5/3 hours. \r<BR>\n" );
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document.write( "Also, the plane has gone 420+420 = 840 miles total.\r<BR>\n" );
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document.write( "Divide the total distance by the total time to get the overall average speed\r<BR>\n" );
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document.write( "r = D/t<BR>\n" );
document.write( "r = 840/(5/3)<BR>\n" );
document.write( "r = 840*(3/5)<BR>\n" );
document.write( "r = 2520/5<BR>\n" );
document.write( "r = 504\r<BR>\n" );
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document.write( "So the average speed is <font color=\"red\">504 mph</font>\r<BR>\n" );
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document.write( "Note: this works for <i>any</i> distance you pick from NY to Atlanta. </SPAN>\n" );
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