document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=600011>Question 600011</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a plane can travel 480 mph in calm air. flying with the wind, the plane can travel 600 miles in the same amount of time it takes to travel 480 miles against the wind. find the rate of the wind.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #379158 by </B><A HREF=/tutors/aboutme.mpl?userid=w_parminder><B>w_parminder(53)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=w_parminder><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=w_parminder><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=379158\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Speed of the plane in calm air = 480 mph<BR>\n" );
document.write( "Let speed of air = X mph\r<BR>\n" );
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document.write( "Effective speed of the plane with the wind = 480 + X<BR>\n" );
document.write( "Effective speed of the plane against the wind = 480 - X\r<BR>\n" );
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document.write( "According to the question,<BR>\n" );
document.write( "Time taken by the plane to travel 600 miles with the wind = Time taken by the plane to travel 480 miles against the wind\r<BR>\n" );
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document.write( "i.e. <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=600%2F%28480%2BX%29=480%2F%28480-X%29 ALIGN=MIDDLE  ALT=\"600%2F%28480%2BX%29=480%2F%28480-X%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >  (using the formula Time = Distance/Speed)\r<BR>\n" );
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document.write( "i.e. <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F%28480%2BX%29=4%2F%28480-X%29 ALIGN=MIDDLE  ALT=\"5%2F%28480%2BX%29=4%2F%28480-X%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "i.e. 4*(480 + X) = 5*(480 - X)\r<BR>\n" );
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document.write( "i.e. 1920 + 4X = 2400 - 5X\r<BR>\n" );
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document.write( "i.e. 9X = 480\r<BR>\n" );
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document.write( "X = 480/9 = 53.33\r<BR>\n" );
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document.write( "So the speed of air is 53.33 mph </SPAN>\n" );
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