Final answer:
To calculate the average speed for the whole trip, divide the total distance by the total time taken.
Step-by-step explanation:
To calculate the average speed for the whole trip, you need to find the total distance traveled and the total time taken. In this case, you drove for 30 minutes at 30 mi/hr and then for another 30 minutes at 50 mi/hr. The total distance traveled is 30 mi + 30 mi = 60 mi. The total time taken is 30 min + 30 min = 60 min = 1 hour. To calculate the average speed, you divide the total distance by the total time: 60 mi / 1 hour = 60 mi/hr.