$13-15$ The Northside 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. towicenti $1$ tow Nanter of asp. Firie f inowgeti Byat Centi $1$