Amandolin string's first harmonic is 392 hz. how long is the string if the wave speed on it is 329 m/s?

Velocity is given by:
velocity=wavelength×frequency
We note that the wavelength of a wave is twice the length of the string (2w) in the first harmonic.
velocity=329 m/s
wavelength=2w
frequency=392
substituting the values in our equation we get:
329=2w(392)
329=784w
solving for w we get
w=329/784
w= 0.41964~0.42 m

Cwill be your correct answer

)because it's going in order of the math sign