Answer
The speed of motorist is 70 mph and the officer should not believe the motorist as he exceeded 20 mph from the speed limit.
Work Step by Step
Substitute $245$ for $L$ in the given formula and calculate $v$.
That is.,
Write $245$ into its prime factors and take square root.
That is.,
$v=2\sqrt{5L}$
$v=2\sqrt{5*245}$
$\begin{align}
& v=2\sqrt{5\times 5\times {{7}^{2}}} \\
& =2\times 5\times 7 \\
& =70
\end{align}$
Thus, the speed of motorist was $70\text{ mph}$.
Since it is greater than $50\text{ mph}$, he was speeding.
