Baltimore Inc. reported pretax GAAP income of $99,000$ during the year. In analyzing differences between GAAP income and taxable income, the company determined that it had properly deducted $$13,000$ in nondeductible fines and added $$7,280$ in tax$-$exempt municipal interest revenue to GAAP income. The statutory tax rate is $25\%.$

I am able to get the non$-$deductible expense $\%$ by mutliplying the non$-$deductible fee of $13,000$ by the statutory rate of $\mathrm{.}25,$ then dividing that by the pretax income. This same method however does not work with the tax$-$exempt.