0.18 Hz 0.36 Hz 2.8 Hz 9.0 Hz
I gave my students this multiple choice question: What is the frequency of ocean waves that have a speed of 18 m/s and a wavelength of 50 m?

Only one answer is correct among these 4 choices:
- 0.18 Hz
- 0.36 Hz
- 2.8 Hz
- 9.0 Hz

Could you tell me which one is correct?

0.36 Hz