The frequency of the wave will be 53.85 Hz
to determine our answer, we can use the following formula "Speed = Wavelength x Frequency."
Speed = 280 m/s
wavelength = 5.2 meters
frequency = ?
meaning, 280 m/s=5.2 times x
divide each side by 5.2
x=700/13 or 53 11/13, or x=53.85