A train is running at a speed of 40 km/hr and it crosses a post in 19.8 seconds. What is the length of the train? Choose one.
A) 190 metres
B) 160 metres
C) 200 metres
D) 220 metres
E) 250 metres

Rationale: "speed of the train , v = 40 km / hr = 40000 / 3600 m / s = 400 / 36 m / s time taken to cross , t = 19.8 s distance covered , d = vt = ( 400 / 36 ) ã — 19.8 = 220 m distance covered is equal to the length of the train = 220 m correct answer is 220 metres d"
Answer: D