Answer:
42 m/s
Explanation:
by definition of the velocity(speed) of a wave,
The velocity of light, v, is the product of its wavelength, λ , and its frequency, f.
V= fλ
frequency - number of occurances in a unit time
(check the graph)
[tex]velocity=frequency*wave.length\\=14Hz*3m\\=42 ms^{-1}[/tex]