Question

Katrina overtakes two person who are working in the same direction in which the train is going @ to kilometre per hour and 4 kilometre per hour and passes in completely 9 and 10 seconds respectively the length of train is

Answer 1

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