Answer
$f=275 Hz$
Work Step by Step
We know that;
$f=\frac{\omega}{2\pi}$
We also know that:
$\omega=\sqrt\frac{1}{LC}$
Combining the two formulas, we find that:
$f=\frac{1}{2\pi \sqrt {LC}}$
We plug in the known values to obtain:
$f=\frac{1}{2(3.1416)\sqrt{(45\times 10^{-3})(6.20\times 10^{-6})}}$
$f=275 Hz$
