document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=889402>Question 889402</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Two aeroplanes pass each other in flight while travelling in opposite directions.Each aeroplane continues on its flight for 45 minutes after which the aeroplanes are 840 km apart. The speed of the first aeroplane is 3/4 of the speed of the other aeroplane. Calculate the average speed of each aeroplane.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #538144 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=538144\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+ ALIGN=MIDDLE  ALT=\"+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the distance in km the faster plane travels<BR>\n" );
document.write( "after they pass each other<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+ ALIGN=MIDDLE  ALT=\"+840+-+d+\"   DISABLED_style= \"max-width:90%; height:auto;\" > km = the distance in km the slower plane<BR>\n" );
document.write( "travels after they pass each other<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+ ALIGN=MIDDLE  ALT=\"+s+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the average speed of the faster plane in km/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%283%2F4%29%2As+ ALIGN=MIDDLE  ALT=\"+%283%2F4%29%2As+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the average speed of the slower plane <BR>\n" );
document.write( "-----------------------------------------------------<BR>\n" );
document.write( "Slower plane's equation:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+=+%283%2F4%29%2As+%2A%2845%2F60%29+ ALIGN=MIDDLE  ALT=\"+840+-+d+=+%283%2F4%29%2As+%2A%2845%2F60%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Faster plane's equation:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+s%2A%2845%2F60%29+ ALIGN=MIDDLE  ALT=\"+d+=+s%2A%2845%2F60%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "Substitute (2) into (1)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+s%2A%2845%2F60%29+=+%283%2F4%29%2As+%2A%2845%2F60%29+ ALIGN=MIDDLE  ALT=\"+840+-+s%2A%2845%2F60%29+=+%283%2F4%29%2As+%2A%2845%2F60%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+s%2A%283%2F4%29+=+%283%2F4%29%2As+%2A%283%2F4%29+ ALIGN=MIDDLE  ALT=\"+840+-+s%2A%283%2F4%29+=+%283%2F4%29%2As+%2A%283%2F4%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+s%2A%283%2F4%29+=+%289%2F16%29%2As+ ALIGN=MIDDLE  ALT=\"+840+-+s%2A%283%2F4%29+=+%289%2F16%29%2As+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+16+ ALIGN=MIDDLE  ALT=\"+16+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+16%2A840+-+12s+=+9s+ ALIGN=MIDDLE  ALT=\"+16%2A840+-+12s+=+9s+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+21s+=+13440+ ALIGN=MIDDLE  ALT=\"+21s+=+13440+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s+=+640+ ALIGN=MIDDLE  ALT=\"+s+=+640+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%283%2F4%29%2A640+=+480+ ALIGN=MIDDLE  ALT=\"+%283%2F4%29%2A640+=+480+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The average speed of the faster plane is 640 km/hr<BR>\n" );
document.write( "The average speed of the slower plane is 480 km/hr<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+=+%283%2F4%29%2As+%2A%283%2F4%29+ ALIGN=MIDDLE  ALT=\"+840+-+d+=+%283%2F4%29%2As+%2A%283%2F4%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+=+%283%2F4%29%2A640+%2A%283%2F4%29+ ALIGN=MIDDLE  ALT=\"+840+-+d+=+%283%2F4%29%2A640+%2A%283%2F4%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+=+%28+9%2F16+%29%2A640+ ALIGN=MIDDLE  ALT=\"+840+-+d+=+%28+9%2F16+%29%2A640+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+840+-+d+=+360+ ALIGN=MIDDLE  ALT=\"+840+-+d+=+360+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+480+ ALIGN=MIDDLE  ALT=\"+d+=+480+\"   DISABLED_style= \"max-width:90%; height:auto;\" > km<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+s%2A%283%2F4%29+ ALIGN=MIDDLE  ALT=\"+d+=+s%2A%283%2F4%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+640%2A%283%2F4%29+ ALIGN=MIDDLE  ALT=\"+d+=+640%2A%283%2F4%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+d+=+480+ ALIGN=MIDDLE  ALT=\"+d+=+480+\"   DISABLED_style= \"max-width:90%; height:auto;\" > km<BR>\n" );
document.write( "OK\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );