Answer
About $50.7 \%$
Work Step by Step
The wavelength of red light is $\lambda=650 \mathrm{~nm}$, and its absorption coefficient is $\mu(650)=0.0034$. We have
$\begin{aligned} T_\lambda(200) & =e^{-\mu(650) \cdot 200} \\ & =e^{-0.0034(200)} \\ & =0.5066,\end{aligned}$
About $50.7 \%$ of red light is transmitted.
