please help solve

Flow Cruiseline offors nightly dinner cruises departing from several cifies on the eastem coast of the United States including Charleston, Baltimore, and Alexandria. Dinner cruise tickets sell for $80 per passenger Flow Cruiseline's variable cost of providing the dinner is $40 per passenger, and the fixed cast of operating the vessels (depreciation, salaries, docking fees, and other expenses) is $240.000 per month. The company's relevant range extends to 11,000 monthly passengers HFlow Cruiseline has a target operating income of $40,000 per month, how many dinner cruise fickets must the company sell