The speed of the sound wave produced in the experiment can be calculated like this:
v = lf
l = wavelength = 0.566 cm = 0.00566 m
f = frequency of wave = 62300 Hz
v = 0.00566*62300 = 352.618 m/s
We also have this equation, relating v, in m/s, to Tc, temperature, in Celsius:
v = 331.5 + 0.6Tc
352.618 = 331.5 + 0.6Tc
Solving for Tc,
Tc = 35.2 C
However, the question asks for temperature in Kelvin.
Tk = Tc + 272.15
Tk = 35.2 + 272.15
Tk = 307.35 K