Q23 - Three million dollars was recently stolen from the Cit

[mshinners]

What does the Question Stem tell us?
Match the Flaw

Break down the Stimulus:
Conclusion: Some of the mayor's staff are suspects for the missing money stolen from the CT's office.
Evidence: The suspects are all former employees of the CT, and the mayor's staff includes former employees of the CT.

Any prephrase?
This is actually a Bad Quantity Overlap inference. It's saying All A's are B's (all suspects are former CT employees) and Some C's are B's (some mayoral staff are former CT employees). It's then trying to conclude that there must be an overlap between A and C. However, this is not a legal quantity overlap inference. So we're looking for two premises: All A's are B. Some C's are B. Thus, Some C's are A.

Correct answer:
B

Answer choice analysis:
A) All "somes", keep moving.

B) All S's are B's. Some B's are C's. (that's reversible) Some C's are B's. And we do conclude some C's are S's. This matches!

C) Two "alls", keep moving.

D) Two "alls", keep moving.

E) The "all" is in the conclusion, but it's supposed to be in the premise. Get outta here.

Takeaway/Pattern: If we didn't sense the quantity overlap inference being made in the argument, the answer choices were there to give us a big hint. Since we had a specific desire for two premises, one "all" and one "some" statement, leading to a conclusion that was "some", there were tons of easy eliminations here.

#officialexplanation

[ttunden]

can someone explain this please, i had to initially skip this due to time constraints and when reviewing i still had difficulty with it

[joseph.m.kirby]

This parallel flaw question is interesting in that it functions like a parallel reasoning question (a flawed one of course).

The argument goes....

P1: Suspects -(all)-> Former Employees
P2: Mayors staff -(includes/has some)-> Former Employees
(P2: We could also say: Former Employees -(some)-> Mayors Staff)
-------
C: Mayor's Staff -(some)-> Suspects

The flaw is that the argument fails to consider that it could be possible that the former employees who are on the mayor's staff did not include any of the suspects.

Perhaps there are 100 Former Employees, of which, 10 are Suspects. So, 90 Former Employees are not suspects. Let's say that 20 of the 90 Former Employees who are not suspects join the mayor's staff. Thus, given this situation, the conclusion of the stimulus would not follow.


(A) P1 doesn't match with stimulus argument (should be all)
P1: Sculptors -(some)-> Famous
P2: Painters -(some)-> Famous
C: Painters -(some)-> Sculptors


(B) matches the argument in the stimulus (the trick is to know the inference related to reversing P2 of the stimulus argument)
P1: Skyscrapers -(all)-> buildings
P2: buildings -(some)-> cabins
C: Cabins -(some)-> Skyscrapers


(C) P1 & P2 don't match with the stimulus argument
P1: Tables -(all)-> furniture
P2: Chairs -(all)-> furniture
C: Tables -(some)-> chairs

(D) Nothing matches!
P1: Supermarkets -(all)-> Sell Food
P2: Asparagus -(all)-> Food
C: Supermarkets -(all)-> Sell Asparagus

(E) P1 and C don't match with the stimulus argument
P1: Dogs -(some)-> pets
P2: Animals -(some)-> pets
C: Animals -(all)-> Dogs

[O LSAT Why Art Thou A Pain]

almost identical to the above poster:

Stimulus:
Conclusion: some
Premises : some and all

So you are looking for something that matches the "some" in the conclusion and "all + some" in the premises.

The only answer choice that does this is B.

a = some some some
c= some all all
d = all all ?
e = "all" in the conclusion and some-some in the premises