Average rate of change

The average rate of change has a relationship with slopes. In this way, we can write the slope of a line as follows:
[tex] Slope=\frac{Change \ y}{Change \ x} [/tex]
To find the Average Rate of Change (ARC), we need to compute the following:
[tex] ARC=\frac{s_{2}-s_{1}}{y_{2}-y_{1}}=slope \\ \\ where: \\ \\ s_{2}: Number \ of \ students \ in \ 2011 \\ s_{1}: Number \ of \ students \ in \ 2001 \\ \\ y_{2}: Year \ 2011 \\ y_{1}: Year \ 2001[/tex]
So:
[tex] ARC=\frac{305-775}{2011-2001}=-47 [/tex]
As you can see we have a negative sign. This means that the enrollment at the college has been decreasing at a rate of 47 students per year.