i'm going to assume that there are 3 mre's /person/day
at 1,250 calories/ mre that's 3750 calories /person/day
for 7 people, over 90 days that's 2,362,500 calories total.
that's enough that split between 12** people it's 2,187.5 calories /person/day, or just around the recommended daily caloric...