逻辑问题求解QAQ

梦想的蝴蝶

newspapaer: in the past two decades, unlike white members, black members of the state legislature increased more than 100%. Consequently, political power of blacks and whites will soon bee substantially equal.
which of the following, if true, most seriously weakens the argument above?
A. in the past two decades, there is no change in the total number of seats the state legislature provided
B. two decades ago, state legislators included 168 blacks and 7614 whites.
C in the past two decades, only 5 states elected blacks as governors
D in the past two decades, the incomes of black families increased more than 80%
E in the past two decades, the proportion of blacks who participated in elections increased a lot

答案选的是B，但是我怎么想都觉得B只是个时间点没法代表时间段啊，为什么不是选C呢？

alzn2765

质疑假设类

前提（因）：in the past two decades, unlike white members, black members of the state legislature increased more than 100%.
结论（果）： political power of blacks and whites will soon bee substantially equal.

前提和结论之间有一个gap: （黑人增长100%只是相对于自己的相对增长，不是相对于白人的相对增长啊！）two decade gao, 黑人立法委员至少是白人立法委员的50%。要削弱结论，直接质疑这个假设就好了。Assumption为假，结论比为假。

C说 in the past two decades, only 5 states elected blacks as governors。反例：two decade gao, 黑人立法委员2人，白人立法委员200人。 in the past two decades, only 5 states elected blacks as governors，每个states选出了40个黑人立法委员，白人立法委员0人。结果现在黑人立法委员202人，白人立法委200人--- political power of blacks and whites will soon bee substantially equal 成立啊！

这就是“相对”与“绝对”的小把戏啊！你的薪水增长200%，马云的薪水不增长。我说你一定挣的比马云多。对不对？

梦想的蝴蝶

alzn2765 发表于 2015-9-24 17:28
质疑假设类

前提（因）：in the past two decades, unlike white members, black members of the state le ...

啊！！听君一席话胜读十年书_(:з」∠)_谢谢！！！

cynthiacheng

又一个疑问，这里的political power难道仅仅指人数吗？我的理解是政治力量应该是人口和权利大小共同决定的呀。C选项说仅有5个黑人当了州长，就是说尽管他们人数增加但政治权利依然很小，所以我觉得C也是对的啊

Bradz

比较一下吧。假设都是每20年增长100%，州长过去20年从0到5，未来40年到20，美国40多个州，这就快一半了。立法会20年前168个黑人，现在336个，未来40年到1344，假设席位不变，白人有6438，离平衡还很远。