Question 1090428
<pre>{{{drawing(400,100,0,1575,-100,100,

line(50,0,1575,0), locate(50,0,A), locate(625,0,B),locate(960,0,C),
locate(1525,0,D),
rectangle(50,0,625,50),rectangle(625,0,950,72),rectangle(950,0,1525,50), 
locate(655,45,TUNNEL),
locate(80,35,matrix(1,2,TRAIN,ENTERING)),
locate(1030,35,matrix(1,2,TRAIN,EXITED)),

locate(290,0,575m),locate(755,0,325m),locate(1190,0,575m)


 )}}}  

Assume that the train is moving from left to right in
the drawing above.

The front of the train begins at B and must travel to D.
So the front of the train travels the distance of BD in
order for the entire train to be completely out of the 
tunnel.

BD = BC + CD = 325 + 575 = 900 meters.

<font size=1>[Note that you could also do it by saying that the end
of the train begins at A and must travel to C.
So the end of the train travels the distance of AC in
order to be completely out of the tunnel. 

AC = AB + BC = 575 + 325 = 900 meters.]</font>

{{{SPEED}}}{{{""=""}}}{{{DISTANCE/TIME}}}

The Distance is 900 meters and the Time = 90 seconds

{{{SPEED}}}{{{""=""}}}{{{matrix(1,2,900,meters)/matrix(1,2,90,seconds)}}}{{{""=""}}}{{{matrix(1,2,10,m/s)}}}

Edwin</pre>