Logical reasoning PrepTest 125 · Section 2 · Question 16

Incorrect. This matches our anticipation for the strength that we can infer, so we should see if we can infer it based on the statements. However, this answer is about cats that aren't good hunters, and the stimulus is about cats that are good hunters. This answer is a partial negation of the reversal of the second statement, which isn't a valid transformation.

Incorrect. "A smaller number" is enough to throw this answer choice out. The premises are about percentages—some/most/all tell you about the percentage of a group, not a number. We can't compare "some" of one group to "most" of another to draw any conclusions about group sizes.

Incorrect. This answer is too strong in applying to all cats (and it also discusses bad hunters, not good ones).

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
(1) Good hunter → Can kill prey up to 1/2 body weight
(2) Good hunter → High muscle:fat
(3) Wild cat-most-Good hunter
(4) Domestic cat-some-Good hunter

Answer Anticipation:
Must Be True question with conditionals and quantified statements? Time to brush off our inference skills based on those concepts!

Let's start with our diagram. Most of the statements are straightforward, but our first conditional may be something that you skipped, or diagrammed as a weaker version. However, in stating that good hunters have a certain capacity, the argument is establishing that as true for all good hunters.

With that out of the way, we can see that combining all valid combinations will be very time-consuming (there are 5 first-level inferences to be made). We'll write them out in the Takeaways section for practice, but we're going to anticipate something different here to save some time! Let's think about the strength of the correct answer, and then "backsolve" by looking for an answer at that strength and comparing it to the stimulus to see if it can be inferred.

Can we infer another conditional? Nope. That would require us to chain together two conditionals, and statements 1 and 2 don't chain together. So our answer will be a some or a most statement most likely. Let's head to the answers and start there.

Answer Explanation:
Another some answer, so we need to dig in. To reach this answer, we'd need to combine statements 2 and 4. Can we? Yep—if all good hunters have a high muscle:fat ratio, then those domestic cats that are good hunters have that characteristic.

Key Takeaway:
When you're dealing with a Must Be True question that has a lot of statements that can be combined to form inferences, it's usually fastest to "backsolve"—identify something that will be present in the correct answer (here, the weaker logical force) and then see if you can derive the answers that match that from the stimulus. Here, we ended up needing to consider 2 answers based on that, making it a lot faster than deriving all the combinations!
1+2) Can kill prey up to 1/2 body weight-some-High muscle:fat
1+3) Wild cat-most-Can kill prey up to 1/2 body weight
1+4) Domestic cat-some-Can kill prey up to 1/2 body weight
2+3) Wild cat-most-High muscle:fat
2+4) Domestic cat-some-High muscle:fat
3+4) No inference
1+2+3) Can kill prey up to 1/2 body weight-some-High muscle:fat

Incorrect. This answer is too strong in applying to all of a group.