I've never been good at calculating how much food to provide when catering for a large bunch of people. I either end up with too little or too much but prefer to err on the side of having leftovers/take home bags.
So on Saturday I'm organising the dessert buffet at a party for 75 people and assuming most people will have a piece of cake and maybe something else too, I've got the following:
5 large catering cakes/gateaus (each one says it has 18 slices = 90 slices but 70 if some people take bigger pieces)
2 x large cheesecakes = 28 slices in total
36 cupcakes
24 doughnuts
20 large cookies
All in all there's 108 slices of cake and 80 x assorted doughnuts/cookies etc.
On the assumption that people can get a bit greedy when they see sweet stuff, is that enough?