A man in a train notices that he can count 41 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed is the train travelling?

A. 60 km/hr

B. 100 km/hr

C. 110 km/hr

D. 120 km/hr

Correct Answer :

D. 120 km/hr

Number of gaps between 41 poles = 40 So total distance between 41 poles = 40*50 = 2000 meter = 2 km In 1 minute train is moving 2 km/minute. Speed in hour = 2*60 = 120 km/hour