Topics: Baking, Dozen, Project management Pages: 5 (1580 words) Published: November 11, 2006
Solution to Kristen's Cookie Company (A)
Before answering specific questions, it is useful to make a diagram of the overall process:
Note that in this diagram, activities are arranged in columns to indicate which resources are being used. Inside each activity symbol are written the capacity (in dozens of cookies) and the cycle time (in minutes).

1. How long will it take for you to fill a rush order?
Assuming this order is for one dozen cookies, we will need to do the following: ActivityResourceCycle TimeStart TimeFinish Time
Order EntryE-mail0 minutes00:0000:00
Wash Bowl, MixSelf6 minutes00:0006:00
Fill TraySelf2 minutes06:0008:00
Prepare OvenRoommate1 minute08:0009:00
BakeOven9 minutes09:0018:00
RemoveRoommate0 minutes18:0018:00
CoolNone5 minutes18:0023:00
Pack, Collect MoneyRoommate3 minutes23:0026:00
Therefore, the minimum time to fill an order is 26 minutes. We can illustrate the sequence of events with a Gantt chart:

2. How many orders can you fill in a night, assuming you are open four hours each night? Here is a Gantt chart for two batches of one dozen cookies each. It doesn't take twice as long to produce two batches as it does to produce one batch, because you can start mixing the second batch without having to wait for the whole first-batch process to be completed (you can start washing out the bowl as soon as you finish filling the tray). It is possible to produce two batches in 36 minutes.

In general, a formula for the number of minutes to produce n one-dozen batches is given by this expression:

3. How much of your own and your roommate's valuable time will it take to fill each order? For yourself:
ActivityCycle Time
Wash Bowl, Mix6 minutes
Fill Tray2 minutes
Total8 minutes
ActivityCycle Time
Prepare Oven1 minute
Remove0 minutes
Pack, Collect Money3 minutes
Total4 minutes
This is assuming all orders are for one dozen cookies.
4. Because your baking trays can hold exactly one dozen cookies, you will produce and sell cookies by the dozen. Should you give any discount for people who order two dozen cookies, three dozen cookies, or more? If so, how much? Will it take any longer to fill a two-dozen cookie order than a one-dozen cookie order? First, let's consider costs. The cost of ingredients and the box are the same, no matter how many dozen you bake. So the only resource that might differ with the size of the batch is labor. One Dozen

ActivityResourceCycle TimeStart TimeFinish Time
Order EntryE-mail0 minutes00:0000:00
Wash Bowl, MixSelf6 minutes00:0006:00
Fill TraySelf2 minutes06:0008:00
Prepare OvenRoommate1 minute08:0009:00
BakeOven9 minutes09:0018:00
RemoveRoommate0 minutes18:0018:00
CoolNone5 minutes18:0023:00
Pack, Collect MoneyRoommate3 minutes23:0026:00

Self8
Roommate4
Total Labor Minutes12

Two Dozen
ActivityResourceCycle TimeStart TimeFinish Time
Order EntryE-mail0 minutes00:0000:00
Wash Bowl, MixSelf6 minutes00:0006:00
Fill Tray 1Self2 minutes06:0008:00
Fill Tray 2Self2 minutes08:0010:00
Prepare Oven 1Roommate1 minute08:0009:00
Bake 1Oven9 minutes09:0018:00
Remove 1Roommate0 minutes18:0018:00
Cool 1None5 minutes18:0023:00
Prepare Oven 2Roommate1 minute18:0019:00
Bake 2Oven9 minutes19:0028:00
Remove 2Roommate0 minutes28:0028:00
Cool 2None5 minutes28:0033:00
Pack 1Roommate2 minutes23:0025:00
Pack 2Roommate2 minutes33:0035:00
Collect MoneyRoommate1 minute35:0036:00

Self10
Roommate7
Total Labor Minutes17
Three Dozen
ActivityResourceCycle TimeStart TimeFinish Time
Order EntryE-mail0 minutes00:0000:00
Wash Bowl, MixSelf6 minutes00:0006:00
Fill Tray 1Self2 minutes06:0008:00
Fill Tray 2Self2 minutes08:0010:00
Fill Tray 3Self2 minutes06:0008:00
Prepare Oven 1Roommate1 minute08:0009:00
Bake 1Oven9 minutes09:0018:00
Remove 1...