A train passes a platform in 25 seconds. The same train passes a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, The length of the platform is Choose the correct choice from the following choices.
A) 75 B) 25 C) 26 D) 23 E) 22

Rationale: speed of the train = 54 km / hr = ( 54 × 10 ) / 36 m / s = 15 m / s length of the train = speed × time taken to cross the man = 15 × 20 = 300 m let the length of the platform = l time taken to cross the platform = ( 300 + l ) / 15 = > ( 300 + l ) / 15 = 20 = > 300 + l = 15 × 25 = 375 = > l = 375 - 300 = 75 meter answer is a .
Answer: A