If a 200 m long train crosses a platform of the same length as that of the train in 20 seconds, then the speed of the train is

A. 50 km/hr

B. 60 km/hr

C. 70 km/hr

D. 72 km/hr

if train length is 200
platform length is = train length
=200+200=400m
speed=distance/time
=400/20=20m/s
=20*(18/5)=72km/h

D

Length of train 🚅 = 200m
Platform length= 200m
Time = 20 seconds
So, total length = 200+200 = 400m
Speed = Distance/Time
400/ 20 = 20m/s
Convert into km/hr = 20m/s× (18/5) = 72 km/ hr

72