Formula:

* Speed (v) = Frequency (f) × Wavelength (λ)

Given:

* Frequency (f) = 0.2 Hz

* Wavelength (λ) = 100 meters

Calculation:

* v = 0.2 Hz × 100 meters

* v = 20 meters per second (m/s)

Therefore, the speed of the wave is 20 meters per second.