P$1\mathrm{.}2$ During $2012,$ the Prices and the Wests both filed joint tax returns. For the tax year ended december $31,2012,$ the Prices' taxable income was $$140,000,$ and the Wests had a total taxable income of $$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 Prices and the Wests.

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