document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=260910>Question 260910</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane can fly 160 mph in calm air. Flying with the wind, the plane can fly 500 miles in the same amount of time required to fly 420 miles against the wind. What is the speed of the plane? ok so the answer is supposed to be 13.9 mph but i don't know how to set up me equations.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #192217 by </B><A HREF=/tutors/aboutme.mpl?userid=Greenfinch><B>Greenfinch(383)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Greenfinch><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=Greenfinch><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=192217\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Speed against wind is 160 - v<BR>\n" );
document.write( "Speed with wind is 160 + v<BR>\n" );
document.write( "Time to fly 500 miles with wind is 500/(160 1+ v)<BR>\n" );
document.write( "Time to fly 420 mile against wind is 420/(160 - v)<BR>\n" );
document.write( "And they are equal<BR>\n" );
document.write( "so 500/(160 + v) = 420/(160 - v)<BR>\n" );
document.write( "multiplying up<BR>\n" );
document.write( "500x(160 - v) = 420x(160 + v)<BR>\n" );
document.write( "80,000 - 500v = 67200 + 420v<BR>\n" );
document.write( "12800 = 920v<BR>\n" );
document.write( "v = 12800/920 = 13.913 mph </SPAN>\n" );
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