document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1023364>Question 1023364</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane flies roundtrip between Great Hall and Bradford. The trip is 450 miles each way. The trip with the wind&#8203; (the wind going in the same&#8203; direction) takes 4.5 &#8203;hours, while the trip against the wind takes 5 hours. What is the speed of the plane in still&#8203; air? What is the speed of the&#8203; wind? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #638855 by </B><A HREF=/tutors/aboutme.mpl?userid=fractalier><B>fractalier(6550)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=fractalier><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=fractalier><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=638855\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Call the speed of the plane in still air, r.<BR>\n" );
document.write( "Call the speed of the wind, w.<BR>\n" );
document.write( "Thus the rate with the wind is r + w, and<BR>\n" );
document.write( "the rate against the wind is r - w.<BR>\n" );
document.write( "Now, since rate times time equals distance, we can write<BR>\n" );
document.write( "4.5(r+w) = 450 and<BR>\n" );
document.write( "5(r-w) = 450<BR>\n" );
document.write( "which we can simplify, dividing the time, to<BR>\n" );
document.write( "r + w = 100<BR>\n" );
document.write( "r - w = 90<BR>\n" );
document.write( "Now add these and get<BR>\n" );
document.write( "2r = 190<BR>\n" );
document.write( "r = 95 mph<BR>\n" );
document.write( "so that the wind is<BR>\n" );
document.write( "w = 5 mph </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );