document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=68691>Question 68691</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A plane flies 720 miles against a steady 30 mile per hour head wind and then returns to the same point with wind. If entire trip takes 10 hours, what is plane`s speed in still air? I do not even know where to begin. Please help me. Thank you in advance. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #48878 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley71><B>checkley71(8403)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley71><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=48878\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 10=720/(X-30)+720/(X+30)<BR>\n" );
document.write( "10=(720[X+30]+720[X-30])/(X-30)(X+30)<BR>\n" );
document.write( "10=(720X+21600+720X-21600)/(X^2-900)<BR>\n" );
document.write( "10X^2-9000=1440X<BR>\n" );
document.write( "10X^2-1440-9000=0<BR>\n" );
document.write( "X^2-144-900=0<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 PLANE'S SPEED IN STILL AIR.<BR>\n" );
document.write( "PROOF<BR>\n" );
document.write( "10=720/120+720/180<BR>\n" );
document.write( "10=6+4<BR>\n" );
document.write( "10=10\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );