Question 954712
A train moving 45 kilometres per hour meets and is passed by a train moving 36 kilometres per hour.
 A passenger in the first train sees the second train take 6 seconds to pass him.
 How long is the second train?
:
The relative speed of the two trains is 45 + 36 = 81 km/h
:
At this speed how far can it go in 6 sec
:
{{{(81*1000)/3600}}} = 22.5 meter/sec
6 * 22.5 = 135 meters is the length of the 2nd train