Question $3(2+2+2+2=8$ points$)$

Use Little$$s formula to answer the following two questions.

Little$$s formula: WIP $=$ Flow rate $\backslash$times Flow time.

a$)$ You are working as an HR intern at a large property management company. The company has an employee turnover of $12\%$ a year and an employee base of $80.$ You are given the following task: Find $($i$)$ how many new employees the company must hire every year, and $($ii$)$ the average time an employee spends in the company.

b$)$ Assume the pediatrician$$s office is open $8$:$00$ a$.$m$.$ to noon. Arrivals and departures to a pediatrician$$s office are collected and reported below. Given these, how many patients on average are in the office?

Patient Arrival Departure

$18$:$008$:$30$

$28$:$159$:$30$

$310$:$0010$:$30$

$410$:$1511$:$15$

$510$:$4512$:$00$

c$)$ You started working at a big hardware store. The store turns its inventory of drill driver kits $16$ times per year. If the store has an average inventory of $20$ drill driver kits, what is the average daily sales rate for the kits? $($Assume that there are $360$ days per year$)$

d$)$ A post office serves $108$ customers over its busy period from $1$:$00$ pm to $2$:$30$ pm on a Saturday. At any point in time, there is an average of $15$ people are in the post office $($waiting in line and being served$).$ What is the average amount of time that a person spends in the post office?