OG12-CR94 关于逆否命题和双重否定的疑问

cuteyaoyao

94. Studies in restaurants show that the tips left by customers who pay their bill in cash tend to be larger when the bill is presented on a tray that bears a credit card logo. Consumer psychologists hypothesize that simply seeing a credit-card logo makes many credit card holders willing to spend more because it reminds them that their spending power exceeds the cash they have immediately available.
Which of the following, if true, most strongly supports the psychologists’ interpretation of the studies?
(A) The effect noted in the studies is not limited to patrons who have credit cards.
(B) Patrons who are under financial pressure from their credit-card obligations tend to tip less when presented with a restaurant bill on a tray with a credit-card logo than when the tray has no logo.
(C) In virtually all of the cases in the studies, the patrons who paid bills in cash did not possess credit cards.
(D) In general, restaurant patrons who pay their bills in cash leave larger tips than do those who pay by credit card.
(E) The percentage of restaurant bills paid with a given brand of credit card increases when that credit card’ s logo is displayed on the tray with which the bill is presented.

前面也看了大家很多讨论的帖子，但是发现还是不太清楚
我的理解是：
A(看到信用卡logo)————————>B(tips变多)
但是正确答案的思路是：
否A(看不到信用卡logo)——————>B(tips变少)

但是不是说逆否命题才是正确的吗？
为什么这里要通过双否才能加强题目的结论?

求解啊! 谢谢

春雨Q

LS的解释我记得在feifei里有反例

就是除非是逆否命题，否则不能加强

哪位大牛来解释一下吧

Kya

LZ不必纠结逆否命题和否命题的对错~太死板
A导致B，非A导致非B即可
就是“无因无果”是可以加强因果类型的题目的

cuteyaoyao

求助..!

cuteyaoyao

题目：A(看到信用卡logo)————————>B(tips变多)

正确答案：否A(看不到信用卡logo)—————>否B(tips变少)

我认为：否B(tips变少)——————————>否A(看不到信用卡logo)


不小心打错了.... 麻烦大家了！

cuteyaoyao

正确答案是双否

但是我觉得答案应该是逆否才符合逻辑

谢谢噢！

cuteyaoyao

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