#25 - Specific Reference, Must Be True, Except

[Rachael Wilkenfeld]

Hi BWACHS,

It can be helpful here to think about what this question is asking you to do. Even though it's asking you to continue the paragraph, it's really asking for something that MUST be true. We don't see the relationship in answer choice (B) in the passage. The passage describes the types of collisions are of one of two different types. Either the plates that are colliding are moving the same direction, or two different directions. It isn't a spectrum as answer choice (B) seems to indicate. Answer choice (B) seems to want to say the relationship between subduction and the type of collision is a proportional relationship. That's new information not supported elsewhere in the passage.

Answer choice (B) might feel close, but it's ultimately new, unsupported information.

Hope that helps!

[BWACHS]

Hi Rachel,

Thank you for the response that is helpful, especially the reframe to think of the question as asking what "must be true".

Is that "must be true" framing something I can apply to other RC questions when asked similar types of "what sentence could be added" questions?

Thank you!

[Jeremy Press]

Hi bwachs,

Yes, it is, and if you think about the language of the question stem, it's very much the kind of language we see in Must Be True questions in Logical Reasoning. First, it begins with "Based on the information in the passage," so we're limiting ourselves to the information in the passage and drawing any answer straight from the passage (just like we do when we draw Must Be True answers from the stimulus in Logical Reasoning). Second, it asks for an answer that "most logically completes" the passage, meaning the answer that would be the most logical addition to what is already stated. That's also very similar to a Must Be True answer in Logical Reasoning, which we can think of as a "next logical step" that can be taken from the information in the stimulus. So, ultimately, these "passage completion" questions will generally best be thought of as analogous to Must Be True questions in LR.

I hope this helps!

[BWACHS]

Hi Jeremy,

Thank you that makes so much sense! Hadn't drawn that connection between RC and LR but feels like an "oh yeah!" moment.

Appreciate the help!

[gwlsathelp]

What would you call this question type?

[Stephanie Oswalt]

What would you call this question type?

Hi gwlsathelp,

Thanks for the post! I have moved your post to the thread discussing this question. Please read the above discussion, particularly Rachael and Jeremy's mentions of Must Be True, and let us know if this helps, or if you still have further questions.

Thanks!

[lsatstudent99966]

Hi there,

May I ask if (A) is also unstated in the passage?

The passage tells us that the speed of the "collision zone" or "subduction zone" (I'm not even sure what that means...) is different when the plates are moving in the opposite direction and when they are moving in the same direction. According to the passage, the speed of the "collision zone" or "subduction zone" is faster when the plates are moving in the same direction.

But it doesn't say anything about "the speed of the plates could increase" as in (A), right?

I didn't choose (A) because it obviously won't add any information to the last paragraph. But I still hope to know if (A) comes out of nowhere.

Thank you very much!

[Amber Thomas]

Hi LSATStudent99966!

Answer Choice A states: "Depending on the relationship between plate velocity and mantle, there is always the possibility that plate velocity could increase."

You're absolutely right, there is nothing in the passage discussing the velocity of the plates increasing or decreasing. All we know is that in quiet subduction zones, the collision zone moves with a relatively higher velocity, thereby driving it into the mantle both more quickly and more steeply than it would in other subduction zones. We have no context on the relationship between plate velocity and the mantle potentially causing an increase in plate velocity.

I hope this helps!