Correct Answer - Option 5 : 100 km/h
Calculations:
Length of the train = 200 m
Length of the tunnel = 400 m
Total length = 200 + 400
⇒ 600 m = total distance
And time taken to cross the tunnel = 21.6 sec
⇒ Speed = 600/21.6 m/sec
⇒ Speed = 600/21.6 × 18/5 km/h
⇒ Speed = 100 km/h
The speed of the train is 100 km/h.