A production process at Kenneth Day Manufacturing is shown in Figure S$7\mathrm{.}9.$ The drilling operation occurs separately from, and simultaneously with, the sawing and sanding operation.

A product needs to go through only one of the three assemble operation $($the operation are in parallel$).$

a$)$ If the firm operates $8$ hours per day, $20$ days per month, what is the monthly capacity of the manufacturing process?