A 450 meter train takes 30 sec to cross a man who is walking in the same direction at the speed of 3 km/hr. The speed of the train is:
Answer & explanation
Correct answer: option 4
Let the speed of the train be x km/hr
The relative speed of the train with respect to the man = (x - 3) km/hr
⇒ (x - 3) = \(\frac{450}{30}\) × \(\frac{18}{5}\) (converting m/s to km/hr by multiplying with x\(\frac{18}{5}\))
⇒ (x - 3) = 15 × \(\frac{18}{5}\)
⇒ x - 3 = 54
x = 57
Ans = 57 km/hr