A project has fixed costs of $$1,500$ per year, depreciation charges of $$600$ a year, annual

revenue of $$8,400,$ variable costs equal to two$-$thirds of revenues and the tax rate is $20\%.$

a$.$ If sales increase by $10\%,$ what will be the increase in pretax profits?

b$.$ What is the degree of operating leverage of this project?

Note: Round your answer to $1$ decimal place.