Respuesta :

here's the solution,

we know that,

=》

[tex]wave \: speed = wavelength \times frequency[/tex]

so,

=》

[tex]18 = 3 \times f[/tex]

=》

[tex]f = \dfrac{18}{3} [/tex]

=》

[tex]f = 6[/tex]

frequency = 6 hertz