During$2018,$ the Smiths and the Joneses both filed joint tax returns. For the tax year ended December$31,2018,$ the$$ Smiths' taxable income was $$110,000,$ and the Jones had total taxable income of $$55,000.$

a$.$ Using the federal tax rates given in Table$1\mathrm{.}2,...,$ for married couples filing joint$$ returns, calculate the taxes for both the Smiths and the Joneses.

b$.$ Calculate and compare the ratio of the$$ Smiths' to the$$ Joneses' taxable income and the ratio of the$$ Smiths' to the$$ Joneses' taxes. What does this demonstrate about the federal income tax$$ structure?