40%。 1Single consumption of 4 yuan buffet fast food restaurant 14 yuan. Suppose the daily passenger flow is 100, the daily turnover is 1400 yuan, and the monthly turnover is 42,000 yuan. After deducting the rent, water, electricity and food expenses, the rest is the profit, at least 24,000 yuan. Everything in the buffet is cheaper in the market, such as fish balls, tofu, vegetables and so on. And there is very little real meat.