Question

A train of length 195 m crosses a man running in opposite direction at a speed of 8 km/h. If the speed of the train is 70 km/h, find in how much time the train will cross the man?
1. 9 sec
2. 12 sec
3. 11 sec
4. 8 sec

Answer 1

Correct Answer - Option 1 : 9 sec

Given:

Length of train = 195 m

Speed of man = 8 km/h

Speed of train = 70 km/h

Concept:

\Since the man is running in the opposite direction the speed of the train and the man will add up to give the relative speed.

Formula used:

km/h to m/s conversion = (x km/h × 5/18) m/s

Speed = Distance/time

Calculation:

∵ Relative speed of the train w.r.t to man = (70 + 8) km/h = 78 km/h

78 km/h = [78 × (5/18)] m/s

∴ Time taken by the train to cross the man = 195/[78 × (5/18)] 

= (195 × 18)/(78 × 5)

= 9 seconds