Answer
Diverges
Work Step by Step
Given
$$\sum_{n=3}^{\infty}\left(\frac{3}{11}\right)^{-n}=\sum_{n=3}^{\infty}\left(\frac{11}{3}\right)^{n}$$
Since the series is a geometric series with $|r|=\left|\frac{11}{3}\right|>1$, then the series diverges