以下为一道逻辑题(假设题型),实在不明白: One state adds a 7 percent sales tax to the price of most products purchased within its jurisdiction. This tax, therefore, if viewed 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. (正确答案) 老师讲解: 本来,sales rate(销售税率)= sales tax / sales;(那么one state 的 sales rate就是7%); 现在,sales rate(销售税率)= sales tax / income;并且income越低,其税率越高,推出sales tax 不变。而sales tax不变,根据最初的条件,那么sales*7%不变,即sales不变。然后就推出A答案正确,即:无论收入高低,上街花钱都一样。。。 反正我是不明白,就算sales不变,又跟收入有何关系呢????? 整篇到底是什么意思呢,还请您用自己的语言解释一下吧。
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