The Northshore Bank is working to develop an efficient work schedule for full$-$time and part$-$time tellers. The schedule must provide for efficient operation of the bank including adequate customer service, employee breaks, and so on$.$ On Fridays the bank is open from $9$:$00$ A$.$M$.$ to $7$:$00$ P$.$M$.$ The number of tellers necessary to provide adequate customer service during each hour of operation is summarized here. Each full$-$time employee starts on the hour and works a $4-$hour shift, followed by $1$ hour for lunch and then a $3-$hour shift. Part$-$time employees work one $4-$hour shift beginning on the hour. Considering salary and fringe benefits, full$-$time employees cost the bank $$15$ per hour $($$$105$ a day$),$ and part$-$time employees cost the bank $$8$ per hour $($$$32$ per day$).$