i****h
发帖数: 3161 | 1 Prompt:
All actors are exuberant people and all exuberant people are extroverts, but
nevertheless it is true that some shy people are actors.
If the statements above are true, each of the following must also be true
EXCEPT:
(a) Some shy people are extroverts.
(b) Some shy extroverts are not actors.
(c) Some exuberant people who are actors are shy.
(d) All people who are not extroverts are not actors.
(e) Some extroverts are shy.
(everything is copied from the practice book exactly as it is written) |
d*****t
发帖数: 6 | 2 B
but
【在 i****h 的大作中提到】
: Prompt:
: All actors are exuberant people and all exuberant people are extroverts, but
: nevertheless it is true that some shy people are actors.
: If the statements above are true, each of the following must also be true
: EXCEPT:
: (a) Some shy people are extroverts.
: (b) Some shy extroverts are not actors.
: (c) Some exuberant people who are actors are shy.
: (d) All people who are not extroverts are not actors.
: (e) Some extroverts are shy.
|
a**********m
发帖数: 2098 | 3 I thought it's D.
Just find out several years' casebook reading does nothing helpful to my log
ic reasoning at all.
【在 d*****t 的大作中提到】
: B
:
: but
|
i****h
发帖数: 3161 | 4 The correct answer is B.
But I picked D. STILL couldn't understand WHY B.
小帅大叔, would you help?? Thank you! |
d*****t
发帖数: 6 | 5 D must be true because it's the original statement's 逆否命题. Because all
actors are extroverts, then all non-extroverts are non-actors.
From the prompt we only know something about shy people who are actors (i.e.
, they are extroverts), but we learn nothing about shy people who are not
actors. So it is possible that no shy people who are not actors are
extroverts. Therefore, B is not necessarily true.
【在 i****h 的大作中提到】
: The correct answer is B.
: But I picked D. STILL couldn't understand WHY B.
: 小帅大叔, would you help?? Thank you!
|
s*******1
发帖数: 135 | 6 B. I always draw circles to answer this kind of question. |
x*****n
发帖数: 3422 | 7 being actor => being exuberant => being extrovert
so
not being extravert => not being actor.
Therefore, D must be true
B is a possibility.
【在 i****h 的大作中提到】
: The correct answer is B.
: But I picked D. STILL couldn't understand WHY B.
: 小帅大叔, would you help?? Thank you!
|
t******t
发帖数: 3045 | |
