Reading comp PrepTest 137 · Section 1 · Question 23

Incorrect. This answer has two some premises, so it's not parallel.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Flawed Parallel Reasoning

Stimulus Summary:
BG - $1m was stolen from the City Treasurer's Office
The usual suspects:
(1) Suspect → Former employees of the City Treasurer's Office
(2) Mayor's staff-some-Former employees of the City Treasurer's Office
Therefore - Suspect-some-Mayor's staff

Answer Anticipation:
That this is an overlapping sets/quantifier question isn't immediately apparent. However, it has a conditional premise ("all"), a some conclusion, and that conclusion relates groups that are brought up in multiple premises, so we should have reached that conclusion while working through it.

With that in mind, we need to diagram it out, as we did in our summary. Note that saying that the mayor's staff "includes" former employees just guarantees that some of the mayor's staff is made up of those former employees—when you're uncertain of the quantifier, always go weaker.

With it diagrammed out, we can see that the argument is flawed because it illegally infers from a conditional and a some statement. While an inference can be drawn from that combination, it requires the sufficient condition of the conditional to overlap with either term of the some statement.

So let's find an answer choice that has the same conditional/quantifier structure:
A → B
B-some-C
Therefore - A-some-C

Answer Explanation:
This answer has a conditional that is illegally "chained" into a some statement to conclude a some statement, so this is our answer. You can diagram it out to check, but you should work on your ability to track elements like this without diagramming to save some time! Be sure to check the other answers if you do this, though, and diagram it out if you find a second answer you also like.

Key Takeaway:
Whenever the LSAT is talking about overlap between groups, check to see if there are quantified statements. Especially in Flawed/Parallel Reasoning questions, finding a structure with quantifiers can save you a lot of time and increase your accuracy drastically!

Incorrect. This answer has two conditional premises, so it's a mismatch.

Incorrect. The conclusion here is a conditional, not a some statement, so it's not parallel.

Incorrect. This answer has a conditional conclusion, not a some conclusion, so it's not parallel.