Your plan was to be on the road by 6 A. M. but you did not leave the garage until 10 A. M. You then drove with the cruise control set at 55 mph until stopping at noon. What was your average speed over the time interval from 6 A. M. to noon

18.33 mph

Explanation:

The average speed of an object is defined as the total distance traveled by the object divided by the total time taken to cover the distance.

Average speed = total distance traveled/total time taken

Also, the speed of an object is defined as the distance covered by the object within a specific period.

Speed = distance/time.

Hence, speed of the journey = 55 = distance/2

Distance covered = 55 x 2 = 110 miles

Total time from 6 AM to 12 noon = 6 hours

Average speed = 110/6

                          = 18.33 mph

The average speed over the time interval from 6 AM to noon is 18.33 mph.