The speed of a wave is calculated by the following formula:

Speed (v) = Frequency (f) x Wavelength (λ)

Given:

* Frequency (f) = 7 Hz

* Wavelength (λ) = 14 m

Therefore:

* Speed (v) = 7 Hz * 14 m = 98 m/s

The speed of the wave is 98 meters per second.