- That's a very small highschool. I assume that the class of 27 is just the class that survived. First, you must determine the total number of students that actually go to the school. Once you do, then you can look at the supplies on campus in the cafeteria. From there, you have to decide if electric is still working and if there's a backup generator. Because that will determine if the deep-freeze and refrigeration actually still works. This will also depend on the school district and type of school. For max supplies, you want a school district that hasn't gone to fresh food and veggies. There's also all the vending machines on campus. For schools that have trended out of "un-healthy snacks" there will be a limited amount of food for these students. The variation in numbers in highschools is wide enough that you will have to get more specific for your answer, from the total number of students and teachers on down. Our system, at least here in the USA varies from State to State. I would say that there really is no such thing as an average school.
- Again, I assume these are the only survivors. You call this an average prison, but the data varies widely. Some house almost 1,000 inmates, others only 150. This varies as well by state. Start with this census data or head to wikipedia. There really is no such thing as an average prison. It varies even by county. Some have fields where they grow produce (seriously!), some have weekly deliveries, and others rely on stockpiled goods.
- 6 story condo 46 tenants. Ok, well, are these ALL the tenants or just the survivors? How many condos are in this 6 story condo?
- Cosco 30 people, 12 employees This, finally, is specific enough to answer. The average Cosco stocks about 4,000 different items, and not all of them are food. They are in bulk sizes, and many of them are in the freezer section. For those that aren't, it's quite a lot of food. The first section you really want to look at is water.
Baseline Minimum Daily Water Need: 32 Ounces. That's roughly 10 1/2 gallons per day for your 42 people. Now, some of the food might have water in it, and there are other beverages on the shelves, but most of the stuff that keeps, besides the canned goods.
A full pallet of water supplies roughly 360 gallons of water. The average Cosco will have about 60 of these on-site, going by the pictures I have seen. This is just a guess based on pictures. With this estimate, that's about 21,627 gallons, roughly, unless there has been a run on water. (pallets are not packs, packs are much smaller, a pallet is made up of a bunch of packs.)
That gives you about 2,000 days, if they never bathe.
The food on-site is important, but not as important as the water supply. If there is less than that because of a run on supplies, that changes things. The food, or at least the food kept fresh because it's sealed, will vary, depending on the time of year.
Keep in mind a few factors: The smell of rotting food in cases will bring pests such as rats, and they may tear into the sealed food. I can see this number of people, if they are smart, lasting several years using the supplies here, provided others don't come to take it from them.