document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=110592>Question 110592</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This one if tough! I have been using the distance = rate * time but I can not figure this one, please help!<BR>\n" );
document.write( "A plane flies 720 mi against a steady 30-mi/h headwind and then returns to the same point with the wind. If the entire trip takes 10 h, what is the plane&#8217;s speed in still air?<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 #80573 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=80573\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> in this case, time=distance/rate ... let x=\"speed in still air\"\r<BR>\n" );
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document.write( "(720/(x+30))+(720/(x-30))=10 ... 720(x-30)+720(x+30)=10(x^2-900) ... 1440x=10(x^2-900)\r<BR>\n" );
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document.write( "x^2-144x-900=0 ... (x-150)(x+6)=0 </SPAN>\n" );
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