Another algebra question

in 2000 there were 520 freshman at grove high school. in 2004, there were 565 freshman. find the average rate of change for the number of freshman.

u have two data points and are asked to find the slope.


i will define
x to be the year
and
y to be the number of freshman at grove high school

thus we need to find the slope through the two data points:
(2000, 520) and (2004, 565)

the slope is given by
(y2 - y1) / (x2 - x1)

(565 - 520) / (2004 - 2000)'
= 45 / 4

the average rate of change is an increase of 45 freshmen every 4 years.
equivalent to
11.25 freshmen increase per year.

11 freshman a year