Answer :

Sure! Let's solve this step-by-step.

1. Understand the Problem:
- A train is 250 meters long.
- It takes 15 seconds for the train to completely pass a pole.
- We need to find the speed of the train in kilometers per hour (km/h).

2. Determine the Speed in Meters per Second (m/s):
- Speed is calculated as distance divided by time.
- Here, the distance is 250 meters and the time is 15 seconds.

Speed (in m/s) = Distance (in meters) / Time (in seconds)

Plugging in the values:

Speed (in m/s) = 250 meters / 15 seconds = 16.666666666666668 m/s

3. Convert the Speed from Meters per Second to Kilometers per Hour (km/h):
- To convert meters per second to kilometers per hour, we use the conversion factor: 1 m/s = 3.6 km/h.

Speed (in km/h) = Speed (in m/s) 3.6

Plugging in the speed we found:

Speed (in km/h) = 16.666666666666668 m/s
3.6 = 60.00000000000001 km/h

4. Conclusion:
- The speed of the train is approximately 60 km/h.

Therefore, the train's speed is 60 km/hour.