How many seconds will a 800 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr? Choose the correct choice from the following answers:  A) 25  B) 30  C) 40  D) 48  E) 50

Rationale: "relative speed of the train = 63 - 3 = 60 kmph = 60 * 5 / 18 = 50 / 3 m / sec t = 800 * 3 / 50 = 48 sec answer : d"
Answer: D