Final answer:
The average speed of the person's car over three hours is calculated by adding the distances traveled each hour and dividing by the total time, resulting in an average speed of approximately 62.33 km/h.
Step-by-step explanation:
To calculate the average speed of a person's car over a three-hour period, we add up the distances traveled each hour and divide by the time taken. In this case, the car travels 67 km in the first hour, 45 km in the second hour, and 75 km in the third hour. Thus, the total distance is 67 km + 45 km + 75 km = 187 km. Since the total time taken is 3 hours, we can find the average speed by dividing the total distance by the total time.
Vavg = total distance / total time
Vavg = 187 km / 3 h
Vavg = 62.33 km/h
Therefore, the car's average speed over the three hours is approximately 62.33 km/h, which is a measure of how fast the car is traveling on average over the entire period.