document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=78583>Question 78583</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is the question:  A plane flies 720 mi against a steady 30-mi/h headwind<BR>\n" );
document.write( "and then returns to the same point with the wind.<BR>\n" );
document.write( "If the entire trip takes 10 hrs., what is the plane's speed in the air?\r<BR>\n" );
document.write( "\n" );
document.write( "Please help.  Thank you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #56339 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley75><B>checkley75(3666)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley75><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=56339\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 720/(S-30)+720/(S+30)=10<BR>\n" );
document.write( "[720(S+30)+720(S-30)]/(S-30)(S+30)=10<BR>\n" );
document.write( "(720S+21600+720S-21600)/(S^2-900)=10 COMBINE TERMS & CROSS MULTIPLY<BR>\n" );
document.write( "1440S=10S^2-9000<BR>\n" );
document.write( "10S^2-1440S-9000=0<BR>\n" );
document.write( "S^2-144S-900=0 NOW FACTOR:<BR>\n" );
document.write( "(X-150)(X+6)=0<BR>\n" );
document.write( "X-150=0<BR>\n" );
document.write( "X=150 ANSWER FOR THE SPEED OF THE PLANE IN STILL AIR.<BR>\n" );
document.write( "PROOF<BR>\n" );
document.write( "720/120+720/180=10<BR>\n" );
document.write( "6+4=10<BR>\n" );
document.write( "10=10<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );