A train, 700 m long, passes a railway platform 400 m long in 44 seconds with uniform speed.  What is the time (in seconds) taken by the train to pass a man riding a motorbike, travelling opposite to the direction of the train, at a speed of 36 km/h?

20

Speed of train = \(\frac{700 + 400}{44}\) = 25 m/s

Speed of bike = 36 × \(\frac{5}{18}\) = 10 m/s

Relative speed = 25 + 10 = 35 m/s

Time = \(\frac{700}{35}\) = 20 seconds