$4\mathrm{.}3$ The Evanstonian is an upscale independent hotel that caters to both business and leisure travelers. When a guest calls room service at The Evanstonian, the room$-$service manager takes down the order. The service manager then submits an order ticket to the kitchen to begin preparing the food. She also gives an order to the sommelier $($i$.$e$.,$ the wine waiter$)$ to fetch wine from the cellar and to prepare any other alcoholic beverages. Finally, she assigns the order to a waiter.

Table $4\mathrm{.}8$ Flow time Deluxe Model, Wonder Shed Inc.

Activity Flow time Deluxe $($minutes$)$

$120$

$235$

$345$

$410$

$545$

$630$

$725$

$840$

It takes $4$ minutes to take down the order and to assign the work to the kitchen, sommelier, and waiter. It takes the kitchen $18$ minutes to prepare the typical order. It takes the sommelier $6$ minutes to prepare the drinks for the order. While the kitchen and the sommelier are doing their tasks, the waiter readies a cart $($i$.$e$.,$ puts a tablecloth on the cart and gathers silverware$).$ This takes $10$ minutes per order.

Once the food, wine, and cart are ready, the waiter delivers it to the guest$$s room. It takes the waiter $12$ minutes to deliver the meal to the customer. It takes the waiter additional $4$ minutes to return to the station and debit the guest$$s account. All the times mentioned represent flow time at the various activities, and include the effects of waiting.

Draw a process map for the room$-$service process: from receipt of order to delivery of food

What is the flow time of the process?

What is the effect on the process flow time if the waiter could prepare the cart in $8$ minutes, instead of $10?$

What is the effect on the process flow time if the waiter could deliver the order in $10$ minutes, instead of $12?$

Now redefine the process to begin upon receipt of order, and end upon debit of account. Repeat parts a and b