Question $10($Mandatory$)(10$ points$)$

A bakery with a single sales person for all activities involved in the order receipt and fulfillment process, as shown below, serves customers one at a time. On average there are $6$ customers in the shop $($including the one being served$).$ The average wait time is $6$ minutes.

What is the bakery's approximate process average flow rate $($in customers per minute$)?$ Remember Flow time $=$ task time $+$ wait time.

Activity

Activity $($task$)$ Time per Customer

Greet customer

$15$ seconds

Take order

$2$ minutes

Process and deliver order

$5$ minutes

Print receipt

$1$ minute

Question $10$ options:

a$)$

$0\mathrm{.}37$

b$)$

$1\mathrm{.}70$

c$)$

$0\mathrm{.}35$

d$)$

$0\mathrm{.}42$