For the development of this problem it is necessary to apply the concepts related to the wavelength depending on the frequency and speed of light.
By definition we know that frequency can be expressed as
[tex]f = \frac{v}{\lambda}[/tex]
Where,
v = Velocity
[tex]\lambda =[/tex] Wavelength
Our values are
[tex]v=345m/sec[/tex]
[tex]f=850Hz[/tex]
Re-arrange to find Wavelength
[tex]f = \frac{v}{\lambda}[/tex]
[tex]\lambda = \frac{v}{f}[/tex]
[tex]\lambda = \frac{345}{850}[/tex]
[tex]\lambda = 0.4058m[/tex]
Converting to centimeters,
[tex]\lambda = 0.4058m(\frac{100cm}{1m})[/tex]
[tex]\lambda = 40.58cm[/tex]
Therefore the wavelength of the sound waves in the tube is 40.58cm
