Question

Train overtakes two persons who are walking in the same direction to that of the train at 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. what is the length of the train?
a. 62 m

Answer 1

First person speed = 2*(5/18) = 5/9 m/sec
Second person speed = 4*(5/18) = 10/9 m/sec

Let the length of train is x metre and speed is y m/sec

then,
x
y−
5
9


=9 =>9y−5=x =>9y−x=5.....(i) Also,
x
y−
10
9


=10 90y−9x=100.....(ii) from (i) and (ii), we get, x=50

So length of train is 50 metre