240 meters long train crosses a pole in x seconds, while the train can cross a 360 meters long platform in x+9 seconds. Find the time taken by the train to cross a dog who is running in the direction of the train at speed of 36 km/hr.

Correct option is C

let speed of the train be s km/hr
s = 240/x -----(i)
s = 600/((x+9)) -----(ii)
From (i) and (ii) we get –

So, speed of train = 240/6=40 m/sec
Required time =