GWD3-4

huangsiyan

In the year 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 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 increase 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
选了B，为何选D啊？

seanceserene

after-tax price = pre-tax price + tax

tax涨了，并不等于after-tax price涨。若pre-tax price跌了，可能after-tax price没变，就不能说销售量的下降和after-tax price有关

huangsiyan

"   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"又怎么证明了sales 和tax 有关呢？

tania_zhang

D选项不是用来证明sales 和tax有关的
只是一个assumption
原文推理sales和tax有关时中间少了一环链接，就是2楼说的那个公式

huangsiyan

3Q,就是说题目给出sales和tax有关，然后推断说sales和afterprice有关，问asssumption?-------少了一个tax与afterprice的关系。