document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=205996>Question 205996</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane can travel 640 miles against the wind in the same time it can travel 800 miles with the wind. If the plane can fly 180 mph in calm air, what is the speed 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 #155590 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley77><B>checkley77(12844)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley77><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=155590\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> D=RT OR T=D/R<BR>\n" );
document.write( "T=640/(180-W)<BR>\n" );
document.write( "T=800/(180+W)<BR>\n" );
document.write( "640/(180-W)=800/(180+W)<BR>\n" );
document.write( "640(180+W)=800(180-W)<BR>\n" );
document.write( "115,200+640W=144,000-800W<BR>\n" );
document.write( "640W+800W=144,000-115,200<BR>\n" );
document.write( "1,440W=28,800<BR>\n" );
document.write( "W=28,800/1,440<BR>\n" );
document.write( "W=20 MPH IS THE WIND SPEED.<BR>\n" );
document.write( "PROOF:<BR>\n" );
document.write( "640/(180-20)=800/(180+20)<BR>\n" );
document.write( "640/160=800/200<BR>\n" );
document.write( "4=4 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );