What is the period of a soundwave whose wavelength is 20.0 m? Use values from the book and show ALL of your work.

In one period of a wave, one full cycle (peak through valley and back to peak) passes by. That means that the wave has moved by one wavelength. Wavelength is related to period by the expression:

speed = wavelength / period

If we are given the speed, then we can easily calculate the period at the wavelength of 20 m.

Period = 20 / speed