Answer
The frequency of wave A is $\nu_A\approx8.431\times10^{15}s^{-1}$
The frequency of wave B is $\nu_B\approx3.748\times10^{15}s^{-1}$
Work Step by Step
Since these 2 waves are both electromagnetic radiations, we would find their frequencies according to the following formula $$\nu=\frac{c}{\lambda}$$
$\nu$: frequency of radiation
$c$: speed of light in a vacuum $(c\approx2.998\times10^8m/s)$
$\lambda$: wavelength of radiation
*Wave A:
We already know from part a) that $\lambda_A=3.556\times10^{-8}m$
Therefore, the frequency of wave A is $$\nu_A=\frac{c}{\lambda_A}=\frac{2.998\times10^8m/s}{3.556\times10^{-8}m}\approx8.431\times10^{15}s^{-1}$$
*Wave B:
We already know from part a) that $\lambda_B=8\times10^{-8}m$
Therefore, the frequency of wave B is $$\nu_B=\frac{c}{\lambda_B}=\frac{2.998\times10^8m/s}{8\times10^{-8}m}\approx3.748\times10^{15}s^{-1}$$
