Great Cruiseline offers nightly dinner cruises departing from several cities on the East Coast of the United States including Charleston, Baltimore, and Alexandria. Dinner cruise tickets sell for $$80$ per passenger. Great Cruiseline's variable cost of providing the dinner is $$40$ per passenger, and the fixed cost 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. The breakeven sales are $6,000$ tickets sold.

a$.$ Compute the operating leverage factor when Great Cruiseline sells $8,000$ dinner cruises.

b$.$ If volume increases by $6\%,$ by what percentage will operating income increase?

c$.$ If volume decreases by $4\%,$ by what percentage will operating income decrease?

a$.$ Compute the operating leverage factor when Great Cruiseline sells $8,000$ dinner cruises. $($Round your answer to one decimal place.$)$

First, identify the formula, then compute the operating leverage factor.

$$ Operating leverage factor