Answer: The correct option is
(B) 50 miles per hour.
Step-by-step explanation: Given that Ariel travels 400 miles in 8 hours.
We are to find her rate of change or speed.
We know that
the relation between distance (D), time (T) and speed (S) is as follows :
[tex]S=\dfrac{D}{T}.[/tex]
In the given situation, we have
distance, D = 400 miles and time, T = 8 hours.
Therefore, the speed is given by
[tex]S=\dfrac{D}{T}=\dfrac{400}{8}=50~\textup{miles per hour}.[/tex]
Thus, the required speed is 50 miles per hours.
Option (B) is CORRECT.
