To find Chloe's average speed, we need to divide the distance she traveled (48 miles) by the time it took her (1 hour and 12 minutes).

First, let's convert the time to hours. There are 60 minutes in an hour, so 12 minutes is equal to 12/60 or 0.2 hours. Therefore, Chloe's total travel time is 1 hour 0.2 hours = 1.2 hours.

Now we can calculate her average speed:

Average speed = (Total distance) / (Total time)

Average speed = 48 miles / 1.2 hours

Average speed = 40 miles per hour

Chloe was driving at an average speed of 40 miles per hour.