Question

Confused with this problem

Answer 1

A train is moving with a speed of 40km/h as soon.As another train going in the opposite direction passes by the window the passenger of the first train starts his stopwatch and note that other train passes the window in 3s. find the speed of the train going in the opposite direction if its length is 75m.

Answer 2

What if the train with the passenger with the stop watch was standing still. How would you calculate the speed of the other train?

Answer 3

the speed of other train is 3 sec / 75 m according to the other train ( relative speed )