One state adds a 7 percent sales tax to the price of most products purchased within its jurisdiction. This tax , therefore, if viewes as tax on income, has the reverse effect of the federal income tax: the lower the income, the higher the annual percentage rate at which the income is taxed. The conclusion above would be properly drawn if which of the following were assumed as a premise? A The amount of money citizens spend on products subject to the state tax tends to be equal across income levels. B The federal income tax favors citizens with high incomes, whereas the state sales tax favors citizens with low incomes. C Citizens with low annual incomes can afford to pay a relatively higher percentage of their federal income tax, since their federal income is relatively low. D The lower a state's sales tax, the more it will tend to redistribute income from the more affluent citizens to the rest of society. E Citizens who fail to earn federally taxable income are also exempt from the state sales tax.
tax/income income相等时，买的东西多交的税就多，因为新加了7％到sales price上，收入下降时，买同样的东西交的税在收入中所占比例就越大。就和收入水平不相匹配。 现在加入一个前提使上面的解释成立。 需要限定the lower the income, the higher the annual percentage rate at which the income is taxed. 如果不买东西，那么加入的7％就对income没作用了，要使这个起作用，那么就必须买东西，这样才是征税的条件，那么如果之用一部分收入买东西，那么我们假设这个买的数量有可能很小而极限为没有买的一样，如果要让这个结果完全受到影响，那么就是income全买东西了，所以就会说income lower ，赋税越高。
