Question

The rate of change is constant in the graph. Find the rate of change. Explain what therate of change means for the situation.

Answer 1

In general, given two points on a line, use the formula below to find its slope

$\begin{gathered} (x_1,y_1),(x_2,y_2) \\ \Rightarrow slope=\frac{y_2-y_1}{x_2-x_1} \end{gathered}$

In our case, the graph goes through (0,400) and (12,0); then, calculating its slope

$\begin{gathered} (0,400),(12,0) \\ \Rightarrow slope=\frac{400-0}{0-12}=-\frac{400}{12}=-\frac{100}{3} \end{gathered}$

Thus, the slope is -100/3. It means that the value drops $100 every 3 years. The answer is option B