When a train passes a man standing on a platform, it travels a distance equal to its own length. When a train passes a platform completely, it travels a distance equal to its own length plus the platform length.
The difference in distance covered is equal to the platform length.
Time to pass man = 25 seconds
Time to pass platform = 40 seconds
Extra time taken = 40 - 25 = 15 seconds
This extra time is required to cover the platform length of 200 m.
Speed = TimeDistance
Speed = 15200 m/s
To convert m/s to km/hr, multiply by 518:
Speed = 15200×518
=15×5200×18
=753600
=48 km/hr
Therefore, the speed of the train is 48 km/hr.