Question

Your plan was to be on the road by 9 A.M. but you did not leave the garage until 10 A.M. You then drove with the cruise control set at 50 mph until stopping at noon. What was your average speed over the time interval from 9 A.M. to noon

Answer 1

The average speed over the time interval from 9 A.M. to noon was of 33.33 mph.

Explanation:

The average speed is given by the following equation:

`v = (d)/(t)`

From 10A.M. to noon.

You traveled at 50mph during 2 hours. So how long you traveled?

`50 = (d)/(2)`

`d = 50*2`

`d = 100`

You traveled 100 miles.

What was your average speed over the time interval from 9 A.M. to noon

From 9 A.M. to 10 A.M, you did not travel.

From 10 P.M. to noon, 100 miles.

So 100 miles during 3 hours.

`v = (d)/(t) = (100)/(3) = 33.33`

The average speed over the time interval from 9 A.M. to noon was of 33.33 mph.