Logical reasoning PrepTest 115 · Section 2 · Question 11

Incorrect. This answer concludes that Charles acted selfishly, so we need to look to principle #2. The sufficient conditions to reach that conclusion are either the gift was given to benefit the giver, or that it was less valuable than customary. However, there's no indication that Charles gave his cousin the tickets to benefit himself, and the "customary" value of a birthday present isn't established, so we can't justify this conclusion based on that principle. Note that the principle discusses the value of a present, not how much someone paid for it!

Incorrect. This answer concludes that Emily acted selfishly, so we need to look to principle #2. The sufficient conditions to reach that conclusion are either the gift was given to benefit the giver, or that it was less valuable than customary. However, there's no indication that either of those conditions are met—instead, this argument relies on the recipients reaction to the gift, which is out of scope of the principle

Incorrect. This answer concludes that Amanda's gifts are generous, but there's no principle that justifies that conclusion, so we can immediately rule this answer out.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True (Principle)

Stimulus Summary:
(1) not Intended to benefit recipient OR not Worth more than customary/expected → not Generous
(2) Given to benefit giver OR Less valuable than customary → Selfish

Answer Anticipation:
Must Be True (Principle) questions will frequently present two conditional principles with matching but opposed necessary conditions, and then task you with finding an answer that lines up with one of them.

That's the case here, where we're given two conditional principles. We want to be sure that the judgments (here, not Generous and Selfish) are in the necessary condition, as the answers will present information that lines up with the sufficient condition to allow a conclusion that matches that necessary condition to be drawn. However, there are some interesting wrinkles in this one!

First, let's talk about our diagram of the first conditional. We treated "unless" as "if not." However, there are some additional difficulties when the "unless" term is an AND/OR statement. While we need to apply the negation to both terms in the AND/OR, we also need to apply it to the AND/OR itself. That's how we ended up with the "and" in the plain language as an OR in the conditional. If you had dealt with "unless" using another method, you would have ended up with the contrapositive of our statement. Then, you would have needed to take the contrapositive so that the judgment—not Generous—ended up in the necessary condition.

Second, there is a lot of overlap between the two principles here. The sufficient conditions seem to be individually negated, and the necessary conditions are definitely similar. However, we don't want to see if we can combine the principles in this question type—we're simply trying to apply either to the correct answer. We also don't want to spend a lot of time figuring out if the negations can be related to each other—in other words, don't spend time trying to figure out if not Generous and Selfish are the same term (they aren't;an act can be neither generous nor selfish)! We can apply the principles to answer choices to see if they're justified by them without making this call. Also, it's interesting to note that the two judgments here are not opposed—there's overlap between them. While this is outside the norm, it's unimportant to our work—we still want to see if the answers line up with them.

Let's head to the answers, and find one that lines up with a principle. Note that we have sufficient conditions for two judgments/conclusions—not Generous and Selfish. We don't have sufficient conditions for Generous or not Selfish, so we can rule answers out that reach those judgments without any further consideration!

Answer Explanation:
This answer concludes that Olga's gift was not generous, so we need to look to principle #1. The sufficient conditions to reach that conclusion are either the gift wasn't intended to benefit the recipient, or the gift isn't worth more than is customary/expected. Here, the value of the gift is expected since all children in Olga's family receive a computer as a graduation gift, so the second sufficient condition is met. This justifies the conclusion that her gift wasn't generous, so this is the correct answer.

Key Takeaway:
Must Be True (Principle) questions that provide two conditional principles pretty much always follow the same pattern. You diagram them both out, contrapose them until you get the related judgments in the necessary condition, and then work through the answers by identifying their conclusions and see if they match with the relevant principle.

Incorrect. This answer concludes that Michael's gift was not generous, so we need to look to principle #1. The sufficient conditions to reach that conclusion are either the gift wasn't intended to benefit the recipient, or the gift isn't worth more than is customary/expected. Here, the argument establishes that the gift didn't benefit the recipient, but the sufficient condition is about the intent. Michael's gift was definitely intended to benefit his nephew, so even if it failed to do so, it doesn't trigger that conditional, and so the conclusion here isn't justified by the principle. (The fact that he gave more than ever before also suggests that it was more than expected, thus failing to meet the other sufficient condition, as well.)