document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=387634>Question 387634</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a train is going to a place B and the velocity is 80 km/h. After half an hour, another train leaves for B and its velocity is 100 km/h. both trains arrive in B at the same time. what is the lengh of the route ? \r<BR>\n" );
document.write( "\n" );
document.write( "Please tell me if this solution is good enough!\r<BR>\n" );
document.write( "\n" );
document.write( "S1: speed of train 1 <BR>\n" );
document.write( "S2: speed of train 2 <BR>\n" );
document.write( "D1 = distance travelled by train 1<BR>\n" );
document.write( "D2 = distance travelled by train 2<BR>\n" );
document.write( "t1 : time it took train 1 to get at B<BR>\n" );
document.write( "t2 : time it took train 2(which was late by 1/2 h) to get at B<BR>\n" );
document.write( "When both trains arrive at place B, they would have travelled the same distance and thus: D1 = D2 <BR>\n" );
document.write( "          S1 * t1 = S2 * t2 <BR>\n" );
document.write( "          80 * t1 = 100 * (t1 - 1/2) <BR>\n" );
document.write( "          80t1 = 100t1 - 50 <BR>\n" );
document.write( "          t1 = 2.5 hours<BR>\n" );
document.write( "so the D1 = 80 * 2.5 = 200 km <BR>\n" );
document.write( "also   D2 = 100 * (2.5 - 0.5) = 200 km </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #274032 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=274032\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
document.write( "\n" );
document.write( "Your answer of 200 km is correct!\r<BR>\n" );
document.write( "\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Let x = time it takes for 80km/hr train to get to B<BR>\n" );
document.write( "then<BR>\n" );
document.write( "x- 1/2 = time it takes for 100km/hr train to get to B\r<BR>\n" );
document.write( "\n" );
document.write( "80x = 100(x-1/2)<BR>\n" );
document.write( "multiplying both sides by 2:<BR>\n" );
document.write( "160x = 100(2x-1)<BR>\n" );
document.write( "160x = 200x-100<BR>\n" );
document.write( "0 = 40x-100<BR>\n" );
document.write( "100 = 40x<BR>\n" );
document.write( "100/40 = x<BR>\n" );
document.write( "5/2 hours = x\r<BR>\n" );
document.write( "\n" );
document.write( "Distance then is:<BR>\n" );
document.write( "80(5/2) = 40*5 = 200 km\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );