#25 - All actors are exuberant people and all exuberant

[Administrator]

Complete Question Explanation

Must Be True, Except. The correct answer choice is (B).

The diagram for this problem is as follows:

• Shy people Actors Exuberant Extroverts

Since this is an EXCEPT question, the four incorrect answers will be true, and the one correct answer will not necessarily be true.


Answer choice (A): This is simply a restatement of the last portion of the stimulus: Shy people Actors.

Answer choice (B): This is the correct answer choice. In answer choice (B), while we know that some shy extroverts are actors, we cannot be sure that some are not (it is possible, but because all of them could be, not necessary). Thus, (B) is not necessarily true, and is correct.

Answer choice (C): In C, the group "Some exuberant people who are actors" is the same as "Some exuberant actors" because any exuberant people who are actors fall into the category of actors. Once you read it that way, you can see how C must be true. If some shy people are actors and all actors are exuberant, there must be some exuberant actors who are shy.

Answer choice (D): This is a contrapositive of this portion of the stimulus: Actors Exuberant Extroverts

Answer choice (E): This is simply a restatement of the last portion of the stimulus: Shy people Actors. It's also identical to (A), so both must be incorrect.

[nadiaguo]

This is question 25 from the October 1994 LSAT in Section 1 about shy actors.

Question removed by Admin -- LSAC content cannot be posted.

I diagrammed it as Shy people some Actors --> Exuberant --> Extroverts, but I still don't understand why all extroverts must be actors, because wouldn't that be a mistaken reversal?

[Dave Killoran]

Hi Nadia,

Thanks for the question. First, your diagram is correct, so the problem does not lie there. Second, this is a Must Except question, so the correct answer is not necessarily true. Answer choices (A), (C), (D), and (E) must each be true, and are therefore incorrect. In answer choice (B), while we know that some shy extroverts are actors, we cannot be sure that some are not (it is possible, but because all of them could be, not necessary). Thus, (B) is not necessarily true, and is correct.

Please let me know if this helps. Thanks!

[nadiaguo]

Ah thank you. I confused "must be true EXCEPT" with "must be false."

[reop6780]

Answer A and E are the same thing so i excluded those at first. Answer D is contrapositive for "all actors are extroverts." The problem was answer B and C in that i did not know how to express the relation. For example, how can I combine a group such as "some exuberant people who are actors" in answer C ?

[Jacques Lamothe]

Hey reop6780,

Nice work eliminating A, D and E. In C, the group "Some exuberant people who are actors" is the same as "Some exuberant actors" because any exuberant people who are actors fall into the category of actors. Once you read it that way, you can see how C must be true. If some shy people are actors and all actors are exuberant, there must be some exuberant actors who are shy.

B does not have to be true because it is possible that in the group of people who are shy but not actors, none of them are extroverts.

I hope this explanation helps!

Jacques

[reop6780]

Thank you for the reply. I wanted more specific way of drawing logical conclusion.

When I read this stimuli, I can draw conditional relation in the following way:

Actors -> exuberant

exuberant -> extroverts

shy actors


Also, I can make additional inference such as:

Actors extroverts

shy actors exuberant

shy actors extroverts

shy exuberant

shy extroverts


Hence I could exclude A, D, and E with such relation drawn.

However, it is not easy to EXPRESS the relation in answer B and C.

I wish I could get more specific way by such relation, which basically draws arrows for answer B and C.

So far, I assume B is wrong because some shy extroverts ARE actors based on

shy actors extroverts ..?

[BethRibet]

Hi reop,

Thanks for the continuing engagement. B is actually the right answer choice for this one, it's not wrong. I believe Jacques is explaining to you how you can rule out C, because the question stem here indicates all answers choices but one must be true. Let me know if I've misunderstood!

The way that you've diagrammed here looks fine to me. I think the challenge is not how to express the relationship, but just to be clear on what you're reading in the answer choice, and how it maps on to your diagrams. B does not have to be true, because to be certain, or in the category of "must be true", you would have to change the conditions (in a way that's not supported by the stimulus). What we know is that some shy people are actors, and therefore exuberant, and therefore extroverts. B says that some people who are shy (and extroverted) are not actors. That may very well be true, but given what's stated, and given your diagrams, it doesn't *have* to be. It must be true that some shy people are exuberant, extroverted actors -- but it does not have to be true that some shy people are not in those categories.

Sort of like if we know "some jellybeans are red", in the world of the LSAT, we can't assume "some jellybeans are not red" without more information.

As a general tip, while I so appreciate the tendency to want to be precise and as reliable and mechanical as possible when breaking down logical relationships (as it helps you feel more sure that you're right, and it's a challenging test!), in real-time LSAT conditions, the level of perfection you seem to be wanting to pursue is likely to be incompatible with the fact that this is also a test of speed. So your diagrams are partly to help you avoid making errors based on misreading or interpreting the stimulus, and they also need to be time-aids, compatible with quick resolution. If you're spending a great deal of time trying to exhaustively represent the relationships provided, it will eat up more time then you can give this question. Think of diagramming as a quick technique to help you visualize what you're trying to understand. It doesn't matter how detailed they are if you wind up not finishing 3-4 other questions while you were working them out.

I hope this helps -- good luck!

Beth

[reop6780]

Thanks Beth!

I would never draw perfect diagram whatsoever in the real test, but I need to understand how it is phrased in the correct form. Additionally, the easiest way for me to understand the wording of answer choices is by diagram for these questions.

As long as I understood this, I can move on and find a way to solve these problems much more quickly and precisely without being confused of how it's stated.

Thank you for your advice.

[lolaSur]

Hi!

I diagramed the stimulus like this:

A Exu Extro
Not Extro : Not Exu Not A

I chose B, but I am still not sure why C is a must be true. I still see it as a not necessarily true.

I didn't think that "some" can be used a sufficient trigger in a SN diagram. When is using "some" as a sufficient trigger appropriate?

This is why I think that C is not necessarily true and not MBT:
C states "some exuberant people who are actors are shy"

Some means 1 or all. So while is true that some shy actors are exuberant it is also true that some actors who are exuberant are not necessarily shy. This is because "some" does not necessarily mean all.