Given coordinates on the graph is (4,0), (8,10), (12,20).
We need to find the rate of change for the function graphed.
Actually rate of change is the second name of slope.
So, we need to find the slope between given coordinates.
We know slope formula
Let us choose first two coordinates (4,0), (8,10).
(x1,y1) = (4,0) and (x2,y2) = (8,10).
Plugging values of x1,x2,y1 and y2 in slope formula, we get
Slope=
Therefore, rate of change is 5/2 or $2.5 earned per bookmark sold.
