Marginal versus Average Tax Rates. $($Refer to Table $2\mathrm{.}3.)$ Corporation Growth has $$76,500$ in taxable income, and Corporation Income has $$7,650,000$ in taxable income.

a$.$ What is the tax bill for each firm?

b$.$ Suppose both firms have identified a new project that will increase taxable income by $$10,000.$ How much in additional taxes will each firm pay? Why is this amount the same?