Great Cruiseline offers nightly dinner cruises off the coast of Miami, San Francisco, and Seattle. Dinner cruise tickets sell for $ 50 per passenger. Great Cruiseline's variable cost of providing the dinner is $ 20 per passenger, and the fixed cost of operating the vessels (depreciation, salaries, docking fees, and other expenses) is $ 270000 per month. The company's relevant range extends to 16000 monthly passengers. The breakeven sales are 9000 tickets sold.

a. Compute the operating leverage factor when Great Cruiseline sells 12000 dinner cruises.

b. If volume increases by 8%, by what percentage will operating income increase?

c. If volume decreases by 5%, by what percentage will operating income decrease?