We can find the average rate of change using the following formula:
[tex]\begin{gathered} r=\frac{f(b)-f(a)}{b-a} \\ \end{gathered}[/tex]
Where:
[tex]\begin{gathered} a=3 \\ b=5 \\ f(a)=f(3)=18 \\ f(b)=f(5)=50 \end{gathered}[/tex]
Therefore:
[tex]r=\frac{50-18}{5-3}=\frac{32}{2}=16[/tex]
Answer:
D. 16
