Jorge and Anita, married taxpayers, earn $$150,000$ in taxable income and $$40,000$ in interest from an investment in City of Heflin bonds. $($Use the U$.$S$.$ tax rate schedule for married filing jointly.$)$

Required:

a$.$ If Jorge and Anita earn an additional $$100,000$ of taxable income, what is their marginal tax rate on this income?

b$.$ What is their marginal rate if$,$ instead, they report an additional $$100,000$ in deductions?