William Diesel owns the Fredonia Barber Shop. He employs $5$ barbers and pays each a base salary of $$1,510$ per month. One of the barbers serves as the manager and receives an extra $$580$ per month. In addition to the base salary, each barber also receives a commission of $$8\mathrm{.}40$ per haircut.

Other costs are as follows.

$\backslash$table$[[$Advertising$,$$$300,$per month$],[$Rent$,$$$1,020,$per month$],[$Barber supplies,$$0\mathrm{.}45,$per haircut$],[$Utilities$,$$$150,$per month plus $$0\mathrm{.}15$ per haircut$],[$Magazines$,$$$30,$per month$]]$

William currently charges $$18\mathrm{.}00$ per haircut.

$($a$)$

Determine the unit variable costs per haircut and the total monthly fixed costs. $($Round variable costs to $2$ decimal places, e$.$g$.2\mathrm{.}25.)$

Total unit variable cost per haircut $

Total fixed costs

$