Two for each person would require 200 in total, but that's too easy of an equation, did I misunderstand your question? Of course it depends how big they are to decide number per person.
If you're asking how many would it take to feed a group buffet style with guests serving themselves then I too would like to know this just out of curiosity. We don't do hush puppies for catering due to all the issues with cooking them on site and then having to deal with hot oil for transport after the event. I can say that we use an average of 1pc of cornbread per person but for me I may only grab one piece of cornbread but I'd probably grab 3-4 hush puppies and go back for more if they were real good. I'll throw a wild guess out there and say 3 per person or 300 for 100 people.
