Oh good.
1 bag is ~2000 kcal per meal, and I suppose you can divide that up anyway you want. If you divide it into four meals, that's one cup each. I've seen elsewhere people using a thermos with icecubes to keep their mix cool, but I haven't tried it.
7 days = 28 - 500 kcal meals, OR 21 ~666 kcal meals.
How long does 40km of public transit take you? If you haven't already, now is a good time to get into podcasts to pass the time. Pocket Casts is my go-to for this sort of stuff.