Answer:
8000m/s
Step-by-step explanation:
Speed is the measure of ratio of distance to time taken to cover that distance.
So speed of wave is calculated as the product of wavelength and frequency.
As the wavelength is given as 20 m and the frequency is given as 400 Hz, then the speed will be
Speed = wavelength × Frequency = 20 × 400
Speed of wave = 8000 m/s.
So speed of wave is 8000 m/s.