How many staff you need to serve 150 person in a restaurant?

This depends on the experience level of the servers as well as the type of service, plated, family, or buffet, and the menu, as well as whther there are extra stations or beverage service areas. For a simple, 2-3 line buffet, separate dessert and beverage areas, with a simple menu and skilled servers, it would take 3-4 people in the kitchen and about 10 servers to set up, serve, and clean up this size party.