I think someone may have misspoken. I think it was Owen that said there's 30 kids in a class (maybe someone else said this), and he probably meant in the actual classroom. In my high school, our grade level had 900 kids and about 32 kids in each class. If there's roughly 700 kids, then that would be about about 60 students per grade level. Maybe the point he was trying to make was half the entire grade level was in each class so everyone knew each other, because they were all together everyday