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Complete Question Explanation

Must Be True—Formal Logic. The correct answer choice is (B)

The first premise (the initial part of the first sentence) can be diagrammed as:

RUG = recent university graduates
WEI = consider work environment an important factor in choosing a job

WEI RUG

The second premise (the final part of sentence one) can be diagrammed thus:

SALI = consider salary an important factor in choosing a job

RUG SALI

Because these premises share a common term, RUG, they can be combined:

WEI RUG SALI, therefore: WEI SALI

The inference is that some people who consider work environment to be an important factor in choosing a job also consider salary to be an important factor in choosing a job.

The second sentence introduces two new premises (the third and fourth premises of the stimulus). The third premise is:

SLI = consider stress level an important factor in choosing a job
VE = veteran employees

SLI VE

This premise does have any shared terms with anything presented thus far, so all that can be inferred is the contrapositive:
VE SLI

The final part of the second sentence (premise four) can be represented as:

VPI = consider vacation policy an important factor in choosing a job

RUG VPI

This fourth premise can be combined with the information from the first sentence:

SALI
WEI RUG +
VPI

There are three inferences that result from this combination:

1. WEI SALI (there are some people who consider work environment to be an important factor in choosing a job who also consider salary to be an important factor in choosing a job; this inference was already discussed above)

2. WEI VPI (there are some people who consider work environment to be an important factor in choosing a job who also consider vacation policy to be an important factor in choosing a job; this is answer choice (B))

3. SALI VPI (there are some people who consider salary to be an important factor in choosing a job who also consider vacation policy to be an important factor in choosing a job; this inference is the most difficult but is not presented as an answer choice)

At this point, three strong “some” inferences have been made and one of these will be the correct answer choice.

Answer choice (A): The very first answer choice illustrates the importance of correctly interpreting each clause in the stimulus. Referring back to the first inference made (the combination of the first and second premises in sentence one): there are some people who consider work environment to be an important factor in choosing a job who also consider salary to be an important factor in choosing a job. However, the correct interpretation of that clause means there could be workers who consider work environment important but do not consider salary important (or vice versa).

Answer choice (B): This is the correct answer choice. Diagrammatically this answer choice would be represented as WEI VPI (the second of the three inferences above). Notice that this answer choice combines the first clause with the final clause. It is quite common for the test makers to separate key pieces of information as much as possible within the stimulus.

Answer choice (C): The stimulus does not restrict the range of workers who consider work environment an important factor to just a few recent university graduates. That is, it is possible that all veteran employees consider work environment to be an important factor in choosing a job. In fact, the stimulus does not provide enough information to infer anything about veteran employees except what is explicitly stated – veteran employees are the only employees who consider stress level an important factor in choosing a job (SLI VE).

Answer choice (D): It is true that some people who consider vacation policy an important factor also consider salary an important factor (SALI VPI; the third inference above). However, the stimulus does not eliminate the possibility that some veteran workers consider vacation policy important and do not consider salary important (or vice versa).

Answer choice (E): This answer choice is probably drawn from the fact that all recent university graduates consider salary important and none of them consider stress level important (only veteran employees consider stress level important). However, the veteran employees who do consider stress level an important factor may also consider salary an important factor. Nothing in the stimulus implies that these considerations are mutually exclusive.

[jcough346]

Got this question right but struggled immensely juggling the premises and wording. It seems fragmented and all over the place. Also I think I had some confusion over the terms; "some," "all," and "every."
Originally thought it needed it be conditionally diagrammed but went against that and then made some chart that made zero sense either.
Clarification very much needed. Thanks!

[Adam Tyson]

I'll see what I can do to clean up the fragments, jcough!

"Some" brings up interesting diagramming issues, as it indicates not conditional reasoning but the very closely related formal logic. "Some" means "at least one", and it could mean as many as all. "Some people need air in order to survive" is a true statement, because we all do. "Some people are PowerScore LSAT Instructors in Burbank, CA named Adam" is also true, even though there is just one of me (that I know of!) Formal logic arguments often drive people to draw Venn diagrams - overlapping circles - but we don't because they can be misleading. Instead, we use conditional arrows modified with words like "some" and "most".

This question only has one "some" relationship, and the rest are all purely conditional, so rather than go down the path of formal logic I am just going to leave it with this diagram:

RUG (Recent University Graduate) -some-> WEI (Work Environment Important

We learned a few more conditional claims about those RUGs - they ALL find Salary to be Important (SI) and Vacation to be Important (VI). "All" means all - 100%, total, complete. "Every" means the same thing. All and Every are both Sufficient Condition indicators, so just treat them the same as the word "if". I can now add this multi-conditional info to the diagram:

RUG --> SI + VI

Finally, we learn something about a different group, the Veterans (Vet), and that is that they are the only ones (Necessary indicator there) for whom Stress Level is Important (SLI). That's this diagram:

SLI --> Vet

Notice that we cannot connect anything about Vets to what we know about RUGs, I have no idea how Vets feel about Vacation, Salary, or Work Environment. I do know that RUGs don't care about SLI unless those RUGs are also Vets. That could be true.

To recap, what do I know about RUGs? They care about Salary and Vacation, and at least one of them cares about Work Environment. What do I know about Vets? I know that if you care about Stress Levels, then you are a Vet.

On to the answer choices!

Answer A - I cannot know this to be true, because my diagram gives me no relationship between WEI and SI. I can only tell that there is at least one RUG that cares about both.

Answer B - This is the correct answer, because I know that there is at least one (some) RUG that is in the WEI group, and every RUG is also in the VI group. So, that one RUG is enough to connect those two groups.

Answer C - I have no way of knowing what any Vet thinks about WEI or SI or VI. These two diagrams are completely distinct in that regard. RUGs care about WEI, but that doesn't mean they are they only ones that do, and there is nothing to tell me that a RUG cannot also be a Vet (I know plenty of older folks that have long work histories and then go to college, and I myself went to law school at the age of 32 while working full time at a large corporation).

Answer D - I cannot know that all the VI folks are also SI folks. I know RUGs all care about both, but are there non-RUGs that care about one and not the other? Maybe.

Answer E - Same issue as D here - I just can't know this. I know that SLI proves you are a Vet, but a Vet can also be a RUG, and Vets might be in the SI group even if they are not RUGs.

The authors here tried to confuse you by fragmenting the relationships, as you saw, but by diagramming them one at a time and then looking for ways to connect them, just like in a logic game, you can weld the fragments back together and get a clear picture of everything that you do and do not know. After that, just connect the dots and you are good to go.

For more on formal logic, search our online resources, including this forum, for that phrase. You can also find info on it in the Logical Reasoning Bible.

Hope that helped. Good luck!