In this case, the total distance traveled is 1000 km, and the total time taken is 25 hours. The average speed is then 1000 km / 25 hours = 40 km/hr.
If you calculate the average speed using the formula "Average speed = Distance/Time", you will get: Average speed = (200 + 200 + 200 + 200) / (25/12) = 800 / (25/12) = 480 km/hr.