the table below shows a linear relationship between the average height in feet of trees on a tree farm and the number of years since the trees were planted

| 1 | 3 | 6 |11| 15 |numbers of years since the trees were planted
|10|24|45|80|105|average height(ft)

What is the rate of change of the average height in feet of trees on the farm with respect to the number of years since they were planted
A14ft/yr
B3ft/yr
C7ft/yr
d10ft/yr

3 answers

rate of change = (change in height) / (# years)
There are 4 intervals, so figure the 4 rates
Then take their average

Or, just take the total change over the total # years
you get the answer?
the answer is 7