Wave Properties│Please Help!

Question

The speed of sound in air is about 340 m/s. What is the wavelength of sound waves produced by a guitar string vibrating at 490 Hz?

Answer 1

v = λf so λ = v/f

If v = 340 m/s and f = 490 Hz then

λ = v/f = (340 m/s)/(490 Hz) ≈ 0.69 m