A car is traveling 25 m/s for 30 minutes and 10 m/s for an hour. What is the average speed?

Average Speed = Total distance traveled / Total time taken

In the first part, the velocity is 25 m/s and time taken is 30 min = 1800 s
So, the distance traveled = velocity x time = 25x1800 = 45000 m

In the second part, the velocity is 10 m/s and time taken is 60 min = 3600 s
So, the distance traveled = velocity x time = 10x3600 = 36000 m

So, the total distance traveled = 45000 m + 36000 m = 81000 m
Total time taken = 1800 s + 3600 s = 5400 s

Average Speed = 81000 m / 5400 s = 15 m/s