How long will a passenger sitting at the window of a train moving at a speed of 54 km / h

How long will a passenger sitting at the window of a train moving at a speed of 54 km / h see a train passing by him, the speed of which is 72 km / h and the length is 150 m?

Initial data: V1 (speed of the train in which the person sits) = 54 km / h; V2 (speed of the oncoming train) = 72 km / h; L2 (length of the oncoming train) = 150 m.
SI system: V1 = 54 km / h = 15 m / s; V2 = 72 km / h = 20 m / s.
1) Let’s calculate the speed of trains moving past each other: V = V1 + V2 = 15 + 20 = 35 m / s.
2) Determine the time for the oncoming train to pass by the passenger: t = L / V = 150/35 = 4.29 s.
Answer: The passenger will see the oncoming train for 4.29 seconds.