document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1090623>Question 1090623</A>: <I><SPAN STYLE=\"word-break: break-all;\">  A plane flew from Minneapolis to Atlanta, a distance of 900 miles, against a 30 mph-headwind. On the return <BR>\n" );
document.write( "flight, the 30-mph wind became a tailwind. The plane was in the air for a total of 5 ½ hours. What would <BR>\n" );
document.write( "the plane’s average speed have been without the wind?&#65533; </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #705079 by </B><A HREF=/tutors/aboutme.mpl?userid=jorel1380><B>jorel1380(3719)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jorel1380><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=jorel1380><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=705079\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let s be the speed of the plane in still air. Then:<BR>\n" );
document.write( "900/s+30 + 900/s-30=5.5<BR>\n" );
document.write( "900(s-30)+900(s+30)=5.5(s²-900)<BR>\n" );
document.write( "1800s=5.5s²-4950<BR>\n" );
document.write( "5.5s²-1800s-4950=0<BR>\n" );
document.write( "11s²-3600s-9900=0<BR>\n" );
document.write( "(11s+30)(s-330)=0<BR>\n" );
document.write( "s=-30/11 or 330<BR>\n" );
document.write( "We get a positive value of 330 for the speed of the plane in still air<BR>\n" );
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