Estimated annual number of people for lunch:20 million*30%/$20=300,000

Estimated annual number of people for dinner:20 million*60%/$30=400,000

Dinner is the most crowded, so the number of dining places should be set up according to the demand for dinner

Estimated Number of dinners per day: 400,000/365=1096 people

Necessary seats: 1096/102%*(1+20%)=1289 seats