To develop this problem we require the concepts related to Frequency and their respective way of calculating it.
The formula to calculate the frequency is given by
[tex]f=\frac{V}{\lambda}[/tex]
Where,
[tex]\lambda = wavelength[/tex]
[tex]V= velocity[/tex]
For fundamental mode, wavelength is equal to 4 time the length.
Then,
[tex]\lambda = 4L = 4*7.10m=28.4m[/tex]
Replacing in the first equation,
[tex]f=\frac{2730}{28.4}\\[/tex]
[tex]f= 96.12Hz[/tex]
Therefore the frequency is 96.12Hz