gwd-13-4

In the years following an eight-cent increase in the federal tax on a pack of cigarettes, sales of cigarettes fell ten percent. In contrast, in the year prior to the tax increase, sales had fallen one percent. The volume of cigarette sales is therefore strongly related to the after-tax price of a pack of cigarettes.

The argument above requires which of the following assumptions?

A.      During the year following the tax increase, the pretax price of a pack of cigarettes did not increase by as much as it had during the year prior to the tax increase.

B.       The one percent fall in cigarette sales in the year prior to tax increases was due to a smaller tax increase.

C.      The pretax price of a pack of cigarettes gradually decreased throughout the year before and the year after the tax increase.

D.      For the year following the tax increase, the pretax price of a pack of cigarettes was not eight or more cents lower than it had been the previous year.

E.       As the after-tax price of a pack of cigarettes rises, the pretax price also rises.

答案

看得糊涂,pretax 和aftertax哪个大啊?什么思路啊?

这道题什么思路啊

当香烟的税增加8 cent后，香烟的sales下跌了10%

当税增加前8 cent前，sales只下跌1%

结论：sales和税后价格是密切相关的。因为税后价格高了，所以sales下降。成立的前提是香烟税前的价格不能减少。

D取非：在加了税的年份里，如果除掉税，香烟原本的价格就比之前低了8 cent甚至更多，这样的话，就算再加上税，价格是不会高于之前的价格的，那么他的结论 sales与税后价格密切相关就不能成立，削弱。

不知道这样清楚么？