For a standing wave on a string, the wavelength is equal to twice the length of the string:
[tex]\lambda=2 L[/tex]
In our problem, L=50.0 cm=0.50 m, therefore the wavelength of the wave is
[tex]\lambda = 2 \cdot 0.50 m = 1.00 m[/tex]
And the speed of the wave is given by the product between the frequency and the wavelength of the wave:
[tex]v=\lambda f = (1.00 m)(440 Hz)=440 m/s[/tex]
