Answer:
52 Hz
Step-by-step explanation:
We can divide the speed by the wavelength to find the number of waves propagated in one second:
(130 m/s)/(2.5 m/wave) = 52 waves/s
The SI unit of frequency is the Hertz, equal to one cycle per second.
The frequency of this wave is 52 Hz.
_____
<em>Additional comment</em>
The use of the unit Hz to signify frequency was adopted in 1933, but did not replace the unit "cycles per second" (CPS) until a number of years later.
