求PREP-DS-1-165

oldereaper

165

 

Of the 1,400 college teachers surveyed, 42 percent said that they considered engaging in research an essential goal.  How many of the college teachers surveyed were women?

(1) In the survey, 36 percent of the men and 50 percent of the women said that they considered engaging in research an essential goal.

(2) In the survey, 288 men said that they considered engaging in research an essential goal.

答案: A

为啥不是D呢?

D也能算出来啊?

请高人指教

oldereaper

哦, 我知道我的问题出在那里了

呵呵,谢谢

cooperqi

说的不错,我想LZ是把题目问的问题没弄清楚,问的是被调查总的女的数,不是那些considered engaging in research an essential goal的女的数~

xiayizhang

B 是不能够推出结论的。

用M F 代表 男和 女的人数， 用m f 代表男 和女中认同研究的人数

则 M+F=1400；

 m+f=1400*42%=588;

现在你会发现，由于mf分别在MF中占得比例并没有确定下来， 则上述方程带入m=288后，并不能明确得出有关M，F 的确定值。

所以不充分。

chwayne

1通过两个二元一次方程可以解出,600women.......in the survey.

2明显条件不够,只能算到200 women......an essential goal.

应该没错吧