Final answer:
The average speed of the train is calculated by dividing the distance traveled, 350 km, by the time taken, 2.5 hours, resulting in an average speed of 140 km/h.
Step-by-step explanation:
To find the average speed of the train, we use the formula for average speed, which is the total distance traveled divided by the total travel time. In this case, the train traveled a distance of 350 km in 2.5 hours. We calculate the average speed (Vavg) as follows:
Vavg = distance / time
Vavg = 350 km / 2.5 h
Vavg = 140 km/h
Therefore, the average speed of the train was 140 kilometers per hour (km/h).