\(5.0 \mathrm{kmol}\) of \(60.0 \mathrm{~mol} \%\) methanol and \(40.0 \mathrm{~mol} \%\) water are batch distilled in a system with a still pot and a column with one equilibrium stage (two equilibrium contacts total). Distillate concentration is constant at 80.0 \(\mathrm{mol} \%\) methanol. The final still pot concentration is \(36.0 \mathrm{~mol} \%\) methanol. Reflux is a saturated liquid, and L/D varies. Assume CMO.

a. Find \(\mathrm{D}_{\text {total }}\) and \(\mathrm{W}_{\text {fin }}\) (kmoles).

b. Find the final value of the external reflux ratio L/D.

Note: This problem can be solved without resorting to guess-and-check.