Super Cruiseline offers nightly dinner cruises off the coast of Nanaimo and Victoria. Dinner cruise tickets sell for $50 per passenger. Super Cruiseline's variable cost of providing the dinner is $10 per passenger, and the fixed cost of operating the vessels (depreciation, salaries, docking fees, and other expenses) is $280,000 per month. The company's relevant range extends to 24,000 monthly passengers. If Super Cruiseline has a target operating income of $60,000 per month, how many dinner cruise tickets must the company sell?