Yes. If Kristen and roommate can only do their own job, the max order(order by order) they can process is 8 orders a night. But if they can cross-training, would 1.
Receive order print and reply Roommate 1 minute/order
Mix ingredients Kristen 6 minutes /max 3trays
Spooning cookies onto tray Kristen 2 minutes/tray
Cookies in oven Roommate 10 minutes/tray
Cool down cookies Roommate 5 minutes/tray
Pack Roommate 2 minutes/tray
Accept payment Roommate 1 minute/order
2.
(1) Spooning cookies onto tray Cookies in oven
(If receive a 2-dozens order) While Kristen is spooning cookies onto tray, the first tray she finished can send to roommate to put into oven. At the mean time, Kristen can spoon the second tray.
(2) (If receive a 2-dozens order) While cooling down the first tray of cookies, roommate can put second tray into oven.
(3) (If receive a 2-dozens order) After the first tray cool down, can pack directly. At the same time, second tray of cookies should be in the oven.
3.
According to the answer of 1st question shown. So, amount of time to process a dozen of cookies is 27minutes (1+6+2+10+5+2+1=27)
4.
(1) If Kristen proceed order by order, will be 8 orders of single dozen per night. 4 hours=240 minutes, 240/27=8.88 orders.
(2) If Kristen and roommate can proceed different orders at the same time, that is
240minutes/45 minutes = 5.3
5.3x2orders =10.6, 10 orders
be able to process more orders. Example shown below for 4hours performance of Kristen and roommate
As the chart shown above, 4 hours of cross-training process can almost complete single dozen orders.
6.
If Kristen and roommate still process order by order(process one order at one time), buying another oven can only reduce the baking time for 2-dozens