Some visitors to the park engage in practices that seriously harm the animals. Surely, no one who knew that these pra...

Mehran on May 1, 2016

@horsehhorse sure, let's take a look!

"Some visitors to the park engage in practices that seriously harm the animals."

VP-some-EPSHA
EPSHA-some-VP

"Surely, no one who knew that these practices seriously harm the animals would engage in them."

K ==> not EPSHA
EPSHA ==> not K

"So it must be concluded that some of the visitors do not know that these practices seriously harm the animals."

VP-some-not K
not K-some-VP

This is a valid argument and the premises are combined as follows:

VP-some-EPSHA ==> not K

To conclude:

VP-some-not K

Hope this helps! Please let us know if you have any other questions.

esther on July 31, 2018

someone said a quick trick for this question would be to look for an answer choice with a similar set up as the question.

thus the question is in Some-None- some
therefore we should go with C because its also set up as some-none-some

is this a legit strategy

Ceci on October 6, 2018

"someone said a quick trick for this question would be to look for an answer choice with a similar set up as the question.

thus the question is in Some-None- some
therefore we should go with C because its also set up as some-none-some

is this a legit strategy"

please respond to this because it's what I do!

Also, what is the correct answer?

kfjones on January 29, 2019

someone said a quick trick for this question would be to look for an answer choice with a similar set up as the question.

thus the question is in Some-None- some
therefore we should go with C because its also set up as some-none-some

is this a legit strategy

please respond!

Ravi on February 11, 2019

@esther, @Ceci, and @noname,

Great question. On parallel reasoning questions, it is important to
make sure that the argument structure of the answer choices mirrors
the structure we see in the stimulus. In this particular question,
yes, this trick does work. HOWEVER, keep in mind that it's best not to
rely on gimmicky tricks like this because on more difficult questions,
these types of shortcuts will not work. Some questions like this that
are more difficult will have two or three answer choices with the same
"some-none-some" language that we see in the stimulus.

On these questions, it's always best to have a firm grasp of the
argument, and if you need to, don't be afraid to diagram.

As Mehran notes, the stimulus contains a valid argument, and the
premises are combined to prove the conclusion:

VP-some-EPSHA - >not K

to conclude that

VP - >not K

(C) says, "Some of the people polled live outside the city limits.
However, no one who can vote in city elections lives outside the city.
Therefore some of the people polled cannot vote in the upcoming city
election."

(C) can be diagrammed as

People polled-some-outside city limits
outside city limits-some-people polled

vote in city elections - >/outside city limits
outside city limits - >/vote in city elections

conclusion: people polled-some-/vote in city elections

This argument is valid, as the premises can be combined to justify the
conclusion

people polled-some-outside city limits - >/vote in city elections

to conclude

people polled-some-/vote in city elections

This valid argument structure matches what we found in the stimulus.

While that trick you guys mentioned would work for this question,
there are lots of others where it wouldn't work. Focus on
understanding the argument structure, and that will help you to get
this type of question right every time—even when it's really
difficult.

Does this make sense? Let us know if you have any more questions!

dannyod on February 18, 2019

Is B incorrect because it concludes an affirmative (the mayor DID denounce supporters), while the original passage concludes a negative (some visitors DO NOT know)? Working quickly, I assumed B matched the basic structure (combing a some statement with a sufficient --> necessary statement), so the only difference between B and C seems to be the outcome.

More general question: must the answer to a parallel reasoning question match the outcome of the stimulus in terms of being affirmative or negative? I.e. if the stimulus concludes a negative, the answer must also conclude a negative? Please lmk if that doesn't make sense and I can rephrase. Thanks!

Ravi on February 19, 2019

@dannyod,

Great question.

(B) says, "Some of the people who signed the petition were among the
mayor’s supporters. Yet the mayor denounced everyone who signed the
petition. Hence the mayor denounced some of her own supporters."

The reason (B) is wrong is because it as an all/affirmative statement
instead of the no/negative statement that we see in the stimulus. Your
analysis is correct.

Regarding your second question, in parallel reasoning questions, you
generally want to see the same type of conditionality and/or
quantifier language used in the answer choices that you see in the
stimulus. Of course, there could be exceptions to this, but they would
likely be answer choices that were framed in the negative because
their logical structure mirrored the contrapositive of the statement
in question in the stimulus.

Does that make sense? Let us know if you have any other questions!

dannyod on February 23, 2019

Got it, yes that makes sense and is very helpful. Thank you!

Ravi on February 23, 2019

@dannyod, wonderful! I'm happy to hear that it makes sense. Let us know if you have any additional questions—we're here to help!

Nishant-Varma on May 27, 2020

So we could have a parallel reasoning question in which the answer choice would contain the contrapositive logic structure of the structure presented in the stimulus?

Nishant-Varma on May 27, 2020

But the quantifiers and conditionality used must the same, right?