document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=156483>Question 156483</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 2 cars race around a circular track, in opposite directions, at constant speeds.  They start at the same point and meet every 30.0 seconds. If they move in the same direction, they meet every 120.0 seconds.  If the track is 1800 meters long, what is the speed of each car? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115291 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=115291\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 2 cars race around a circular track, in opposite directions, at constant speeds.<BR>\n" );
document.write( " They start at the same point and meet every 30.0 seconds. If they move in the<BR>\n" );
document.write( " same direction, they meet every 120.0 seconds. If the track is 1800 meters<BR>\n" );
document.write( " long, what is the speed of each car?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Change seconds to min in the problem<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let a = speed of car a (in meters/min)<BR>\n" );
document.write( "Let b = speed of car b<BR>\n" );
document.write( ":<BR>\n" );
document.write( ".5(a+b) = 1800<BR>\n" );
document.write( "Multiply equation by 2<BR>\n" );
document.write( "a + b = 3600<BR>\n" );
document.write( ":<BR>\n" );
document.write( "2(a-b) = 1800<BR>\n" );
document.write( "Divide both sides by 2<BR>\n" );
document.write( "a - b = 900<BR>\n" );
document.write( ":<BR>\n" );
document.write( "a + b = 3600<BR>\n" );
document.write( "a - b = 900<BR>\n" );
document.write( "--------------adding eliminates b<BR>\n" );
document.write( "2a = 4500<BR>\n" );
document.write( "a = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4500%2F2 ALIGN=MIDDLE  ALT=\"4500%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a = 2250 meters/min (<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%282250%2A60%29%2F1000 ALIGN=MIDDLE  ALT=\"%282250%2A60%29%2F1000\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 135 km/hr)<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Find the speed of b<BR>\n" );
document.write( "a + b = 3600<BR>\n" );
document.write( "a + 2250 = 3600<BR>\n" );
document.write( "a = 3600 - 2250<BR>\n" );
document.write( "a = 1350 meters/min (<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281350%2A60%29%2F1000 ALIGN=MIDDLE  ALT=\"%281350%2A60%29%2F1000\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 81 km/hr) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );