Physics question about AC generator

Question

The AC generator rotation frequency is 16.5 Hz. The generator generates 50 Hz alternating current. How many pairs of magnetic poles this generator has?

The correct answer is 3 pairs.

Answer 1

If you rotate only one pair of magnetic poles, then the frequency of AC current will be 16.5 Hz. If you want to have frequency 50 Hz, then you need to have n = 50 Hz : 16.5 Hz = 3 pairs of magnetic poles.

So, the correct answer is 3.