Intermediate Algebra, Chapter 3, 3.2, Section 3.2, Problem 82

Determine and interpret the average rate of change illustrated in each graph.








The slope formula applied to any two points on a line and that gives the average rate of change in $y$ per unit change in $x$, where the value of $y$ depends on the value of $x$.

Based from the graph, the two points are $(1,50)$ and $(2,100)$.




$
\begin{equation}
\begin{aligned}

\text{average rate of change} =& \frac{\text{change in amount saved}}{\text{change in number of months}}
\\
\\
=& \frac{100-50}{2 - 1}
\\
\\
=& \frac{50}{1}
\\
\\
=& 50

\end{aligned}
\end{equation}
$



It shows that the amount saved is increasing by $\$ 50$ per month.