document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1076780>Question 1076780</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane flies 600 miles west (into the wind) and makes the return trip following the same flight path. The effect of the jet stream on the plane is 15 miles per hour. The round trip takes 9 hours. What is the speed of the plane in still air? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #691392 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=691392\">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( "600/s+15 + 600/s-15=9<BR>\n" );
document.write( "600(s-15)+600(s+15)=9sē-2025<BR>\n" );
document.write( "9sē-1200s-2025=0<BR>\n" );
document.write( "3sē-400s-675=0<BR>\n" );
document.write( "(3s+ 5)(s-135)=0<BR>\n" );
document.write( "s=-5/3 or 135<BR>\n" );
document.write( "Ignoring the negative result, we get the speed of the plane in still air to be 135 mph. &#9786;&#9786;&#9786;&#9786; </SPAN>\n" );
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