Question

find the average rate of change over the interval 10, 40

Explanation:

Step1: Identify f(10) and f(40)

From the graph: $f(10)=400$, $f(40)=200$

Step2: Apply average rate formula

Use $\frac{f(b)-f(a)}{b-a}$ for $[a,b]=[10,40]$
$\frac{f(40)-f(10)}{40-10}=\frac{200-400}{30}$

Step3: Calculate the result

$\frac{-200}{30}\approx-6.7$

Answer:

-6.7