Rate of change of profit for this period is $2750 per month
Solution:
Given that,
Profit of $6500 in January and $17,500 in May
To find: Rate of change
Since,
January is the first month of the year (1) while May is the fifth month (5)
Therefore, we get two points
(1, 6500) and (5, 17500)
Using these points we can find the rate of change in profit for this time period
The rate of change using the following formula:

Here from the points,

Therefore, rate of change is given as:

Thus rate of change of profit for this period = $2750 per month