Andy’s average driving speed for a 4-hour trip

was 45 miles per hour. During the first 3 hours
he drove 40 miles per hour. What was his
average speed for the last hour of his trip?

To calculate Andy's average speed for the last hour of his trip, we need to find out how far he traveled during that hour.

We know that Andy's average speed for the entire 4-hour trip was 45 miles per hour. This means that he traveled a total distance of 45 miles per hour * 4 hours = 180 miles.

During the first 3 hours, Andy drove at a speed of 40 miles per hour. So, the distance he covered in the first 3 hours was 40 miles per hour * 3 hours = 120 miles.

To find out how far Andy traveled during the last hour, we can subtract the distance he covered in the first 3 hours from the total distance of the trip.

Distance covered in the last hour = Total distance - Distance covered in the first 3 hours
Distance covered in the last hour = 180 miles - 120 miles
Distance covered in the last hour = 60 miles

Therefore, Andy's average speed for the last hour of his trip can be calculated by dividing the distance covered in the last hour by the time taken for that hour.

Average speed = Distance covered in the last hour / Time taken for the last hour
Average speed = 60 miles / 1 hour
Average speed = 60 miles per hour

So, Andy's average speed for the last hour of his trip was 60 miles per hour.