document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=943101>Question 943101</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane can fly 390 mph in still air. If it can fly 220 miles downwind in the same amount of time it can fly 170 miles upwind, find the velocity of the wind. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #574965 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=574965\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A plane can fly 390 mph in still air. If it can fly 220 miles downwind in the same amount of time it can fly 170 miles upwind, find the velocity of the wind.<BR>\n" );
document.write( "***<BR>\n" );
document.write( "let w=speed of wind<BR>\n" );
document.write( "390+w=speed of plane downwind<BR>\n" );
document.write( "390-w=speed of plane downwind<BR>\n" );
document.write( "travel time=distance/speed(same for downwind and upwind)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=220%2F%28390%2Bw%29=170%2F%28390-w%29 ALIGN=MIDDLE  ALT=\"220%2F%28390%2Bw%29=170%2F%28390-w%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "220(390-w)=170(390+w)<BR>\n" );
document.write( "85800-220w=66300+170w<BR>\n" );
document.write( "390w=19500<BR>\n" );
document.write( "w=50<BR>\n" );
document.write( "speed of wind=50 mph </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );