Logical reasoning PrepTest 132 · Section 4 · Question 15

Incorrect. This answer is about what jewels should be collected, not what the value of these jewels are, so this answer doesn't connect to the conclusion.

Incorrect. There's no discussion of market demand in the stimulus, and the argument relies on aesthetic pleasure to determine value, so this answer is out of scope.

Incorrect. Without connecting to the value mentioned in the conclusion, this answer can't justify the reasoning in the argument.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Principle (Strengthen)

Stimulus Summary:
Since the naked eye can't tell a counterfeit diamond from a real one, they give equal aesthetic pleasure, and thus should be valued the same.

Answer Anticipation:
Principle (Strengthen) questions generally feature a stimulus that makes a judgment in the conclusion based on a set of facts, and the correct answer connects those facts to the judgment.

Here, the conclusion is that two things should have the same value—real and fake diamonds. Why does the author argue that they should have equivalent value? Because they give an equal amount of aesthetic pleasure. However, there's no indication that aesthetic pleasure is what should determine the value of a diamond, so the correct answer will need to connect those ideas:

The value of a diamond should be determined by the amount of aesthetic pleasure it provides.

Answer Explanation:
This answer connects the premise to the conclusion—two diamonds give equal aesthetic pleasure, so they should have equal value. If value is solely determined by aesthetic pleasure, then that argument is valid.

Key Takeaway:
Make sure that the answer you select in a Principle (Strengthen) question connects to the conclusion. It's rare for the correct answer in one of these questions to not do so, so make sure you have a really good justification for picking an answer that doesn't mention concepts in the conclusion.

Incorrect. The argument's conclusion isn't about what jewel collectors should or shouldn't buy, so this answer is out of scope.