Excluding stoppages, a train travels at 72 km/h and including stoppages, its average speed is 60 km/h. For how many minutes does the train stop per hour?

Question: Excluding stoppages, a train travels at 72 km/h and including stoppages, its average speed is 60 km/h. For how many minutes does the train stop per hour?

Solution:
At its moving speed of 72 km/h, the time required to cover 60 km is:
∴ Time moving = distance/speed
= 60 km/72 km/h
= 60/72 hours
= 5/6 hours
= (5/6) × 60 minutes
= 50 minutes

We know,
1 hour = 60 minutes

∴ Stopping time = 60 - 50 = 10 minutes

∴ The train stops for 10 minutes per hour.