Time$-$For$-$Us has set up a booth in a shopping mall to sell calendars during the holiday season. The business can purchase the calendars for

$$2\mathrm{.}69$

each. It plans to set the unit price at

$$9\mathrm{.}99$

$.$ During the time it is in business, it must rent equipment for

$$190$

per day, and pay wages of

$$321$

per day. Answer each of the following independent questions.

$($a$)$How many calendars must the business sell each day to break even?

$($b$)$If it decreases the wages to $$240\mathrm{.}70$ per day, how many must it sell each day to break even?

$($c$)$If the business puts the calendars $$on sale$$ at $25\%$ off, what would be the profit if it sold $120$ units in a day?

$($d$)$On the last day the business plans to be in the mall, $200$ calendars will likely remain on hand. If the wages for the day are $$222,$ what is the lowest price it can charge for each calendar and still break even for that day?