Logical reasoning PrepTest 102 · Section 3 · Question 17

NA

Must Be True Questions

~Leisure → ~Devoted to study of natural processes Resources are plentiful → Leisure ~Resources are plentiful → ~Leisure Domesticate plants → Discovery how plants reproduce and grow Those discoveries → Study of natural processes

This question presents us with premises and asks us to find an answer that represents a conclusion that the argument is structured to lead to, so we should approach this as an Argument Completion (Must be True) question. However, if you treated it as a regular Must be True question, nothing wrong with that! The key difference is that here, we’re likely to use almost all, if not all, of the statements in supporting the correct answer. And this question has a lot of conditional logic in it, so we’ll be diagramming! Let’s work through the diagram, and then work through the chain so we can anticipate an answer. The opening line has “unless” as an indicator word, which we treated as “if not,” leading to statement #1. After that, the following two clauses (still in the first sentence) establish what happens when resources are plentiful and when they’re not. Treating “when” as a sufficient indicator leads to #2 and #3. These two statements are negations of each other, which might raise a red flag for you! However, when we’re given both a statement and its negation, we can treat both as true. We’re just not allowed to infer the negation. After that, we get the claim of some anthropologists, so this is likely to be an opposing point - let’s skip over it. Moving on, we see a requirement (“must first have”) for domesticating plants, leading to statement #4, and then we end with what was required (“were the result of”) to make the discoveries in statement #4, leading to #5. (Yes, we cheated a bit in that last one, as it’s more causal than conditional, but this question type builds all statements together, so this will let us get the flow of the argument.) With all of those noted, let’s build them together to get our inference. #2 and #3 are negations of each other, meaning only one is likely to show up in the chain. Since #2 doesn’t chain with #1, but #3 does, it looks like we should skip over #2. And looking at #4 and #5, those chain together, as well. Let’s get those two chains written out, then see if we can put them together: ~Resources are plentiful → ~Leisure → ~Study natural processes Domesticate plants → Discoveries → Study natural processes The chains do share a term, but it’s negated, so let’s take the contrapositive of one and combine them (we’re going to contrapose statement #1, since that’ll let us conclude something about the societies that first cultivated plants, which sounds like something a conclusion would be about): Domesticate plants → Discoveries → Study natural processes → Leisure → Resources are plentiful With all that done, we can now anticipate an answer - the early societies that domesticated plants had plentiful resources.