Final answer:
The unit rate of a car traveling 320 miles in 8 hours is 40 miles per hour. This is calculated by dividing the total distance (320 miles) by the time taken (8 hours).
Step-by-step explanation:
To calculate the unit rate in miles per hour (mph) for a car traveling a certain distance over time, you can divide the total distance by the total time taken. In this case, the car travels 320 miles in 8 hours. To find the unit rate, divide 320 miles by 8 hours, which gives us 40 mph. This means that the car's average speed was 40 miles per hour.