The train moving at an average speed of 15 m / s covered an equal distance of 108 km. how long he had gotten to it.

Initial data: Vav. (average speed at which the train was moving) = 15 m / s; S (distance traveled by the train) = 108 km (10 ^ 8 * 103 m).

The time spent by the train is equal to the ratio of the distance covered by it and the average speed of movement: t = S / Vav.

Calculation: t = 108 * 10 ^ 3/15 = 7200 s (2 h).

Answer: It took the train 2 hours to cover 108 kilometers.