Royal Hellenic Cruiseline offers nightly dinner cruises off the coast of Nanaimo and Victoria. Dinner cruise tickets sell for $ $60$$$60$ per passenger. Royal HellenicRoyal Hellenic $$Cruiseline$\text{'}$s variable cost of providing the dinner is $ $20$$$20$ per$$ passenger, and the fixed cost of operating the vessels$($depreciation$,$ salaries, docking$$ fees, and other$$ expenses$)$ is $ $210$ comma $000$$$210,000$ per month. The$$ company's relevant range extends to $15$ comma $00015,000$ monthly passengers.

Compute the number of dinner cruise tickets it must sell to break even.

a$.$ Use the income statement equation approach.

b$.$ Use the shortcut unit contribution margin$$ approach; perform a numerical proof to ensure that your answer is correct.

c$.$ Use your answers from$($a$)$ and$($b$)$ to determine the sales revenue needed to break even.

d$.$ Use the shortcut contribution margin ratio approach to verify the sales revenue needed to break even.