Remove and cool
Pack & Collect Money
Two batches will not take twice time more. We can start mix the second batch without waiting for the first batch’s finishing (26 minutes). We can start immediately after we finish filling the tray in the first process. We will wait 2 more minutes until 1st batch will be baked to use the owen (because there is only 1 available). So we can produce two batches in 36 minutes. Each extra dozen of cookies will take about 10 minutes.
After the 1st batch which takes 26 minutes Kristen and her roommate can bake a dozen every 10 minutes. If open for 4 hours they can back 6 dozen every 4 hours for a total of 24 dozen.
Time taken by Kristen to perform activity 2 and 3= 6 minutes + 2 minutes = 8 minutes.
Time taken by roommate to perform activities 4 and 7 = 1 minute + 3 minute = 4 minutes.
Discounts can be given to people who order two dozen or more cookies. This is because, Activity 2 (wash bowl, add and mix ingredients) that is performed by Kristen will take only 6 minutes per order for a maximum order size of 3 dozen cookies. So Kristen will spend the same 6 minutes for activity 1 regardless of whether the order quantity is 1,2, or 3 dozens. Similarly, Activity 7 performed by Kristen's roommate will take 3 minute per order regardless of the order size.
As for equipment utilized, since the electric mixer can hold and mix ingredients for up to three-dozen cookies, one mixing bowl is enough for holding them. Since each tray can only hold one-dozen cookies and up to three-dozen cookies can be mixed at the same time, when they are making 3-dozen cookies at the same time, at least 3 trays...