The the Hanson's have reduced the average number of hours they watch tv each day from 5.5 hrs. in march to 2.5 hrs. in june. Find the rate of change in average number of hrs. they watch tv each day.

I think the answer is
rate = 5.5 - 2.5/3
rate = 3/3
rate = 1 hr.

is this correct?

5.5 - 2.5 = 3 hours

3/5.5 = 0.545 = 54.5% rate of change