The price of the buffet should remain unchanged. The first person to eat, facing all the food. He feels worthless. The question is who will be the last person. The person who finally goes to the buffet will definitely choose to eat the same price as the food in the market with the money he used to eat at the buffet, otherwise he will not choose to eat at the buffet. Therefore, food providers who run buffets should ensure the quantity of food. Food is a commodity that easily expires. After this stage, it is waste.