document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=72139>Question 72139</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0395977258/algebrahomeworkh>Algebra and Trigonometry: Structure and Method </A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> When Ace Airlines changed to planes that flew 100 km/h faster than its old ones, the time of its 2800 km Dallas-Seattle flight was reduced by 30 min.  Find the speed of the new plane. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #51569 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=51569\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 2800/(X+100)+.5=2800/X<BR>\n" );
document.write( "(2800+.5X+50)/(X+100)=2800/X <BR>\n" );
document.write( "(2850+.5X)/(X+100)=2800/X NOW CROSS MULTIPLY<BR>\n" );
document.write( "(X+100)2800=X(2850+.5X)<BR>\n" );
document.write( "2800X+280000=2850X+.5X^2<BR>\n" );
document.write( ".5X^2+50X-280000=0<BR>\n" );
document.write( "X^2+100X-560000=0<BR>\n" );
document.write( "(X-700)(X+800)=0<BR>\n" );
document.write( "X-700=0<BR>\n" );
document.write( "X=700 ANSWER FOR THE SPEED OF THE SLOWER AIRPLANE<BR>\n" );
document.write( "X+100=800 IS THE SPEED OF THE FASTER PLANE.<BR>\n" );
document.write( "PROOF<BR>\n" );
document.write( "2800/800+.5=2800/700<BR>\n" );
document.write( "3.5+.5=4<BR>\n" );
document.write( "4=4<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );