A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 second respectively. The length of the train is.
Let the length of train be x km & its speed be y km/hr
Then, x/(y-2) = 9/(60*60)
and x/(y-4) = 10/(60*60)
9y - 3600x = 18
and 10y - 3600x = 40
y-400x = 2 and y - 360x = 4
Therefore
40x = 2 or x = (2/40 *1000)m = 50 metres