A train passes a platform in 35 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) 280 meter  B) 240 meter  C) 225 meter  D) 200 meter  E) none of these

Rationale: "explanation : speed of the train = 54 km / hr = ( 54 × 10 ) / 35 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 = 35 = > 300 + l = 15 × 35 = 525 = > l = 525 - 300 = 225 meter answer : option c"
Answer: C