Question

The graph represents the relation between the laptop values and the time. The average rate of change (in dollars per year) of the value of laptop over the five-year period is

• A. $-1,100$
• B. $-220$
• C. $-100$
• D. $100$

Answer 1

The correct option is B $-220$

Average rate of change is the same as slope, so we use the slope formula to get the answer.
Slope $=$ $\frac{y_2-y_1}{x_2-x_1}$
From the graph, we get the points of $x$ and $y$ values,
Average $=$ slope $=$ $\frac{100-1200}{5-0}=\frac{-1100}{5}=-220$
The average rate of change is negative because the laptop decreases in value over time.