Logical reasoning PrepTest 132 · Section 2 · Question 21

Incorrect. The stimulus doesn't discuss nurseries that aren't large, so this answer is out of scope.

Incorrect. While most large nurseries guarantee all their plants, there's no indication that small nurseries don't guarantee their plants, or that other aspects of the plants aren't guaranteed in some way, so this answer isn't inferable.

Incorrect. This answer is the "contrapositive" of the opening most statement, but most statements can't be contraposed.

Incorrect. The stimulus states that most large nurseries guarantee their plants are disease-free, not that they actually are, so a nursery selling diseased plants doesn't tell us anything about the likelihood of them being large—guarantees on those plants would.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Large nursery-most-Sell primarily to commercial raspberry growers
Large nursery-most-Guarantee their plants to be disease-free
The shipment from Wally's to Johnson wasn't disease free.

Answer Anticipation:
There are a couple of quantified statements here before a specific scenario is discussed, so we should first see if we can draw an inference by combining the quantified statements, and then we should see if we can apply those quantified statements to the scenario.

For the combination, two most statements that share an initial term can be combined, so we get an inference stating:

Sell primarily to commercial raspberry growers-some-Guarantee their plants to be disease-free

This isn't a particularly interesting inference, however, as it was more or less already established in the stimulus.

So let's see if we can apply either quantified statement to the specific scenario discussed. Wally's is the nursery here, but we don't know if it's a large nursery, so we can't say that these statements apply to it. And since we can't take contrapositives of most statements, it doesn't appear there's any inference that can be drawn just from the statements in the stimulus.

Since that's the case, then it's likely the correct answer will add information that allows these quantified statements to be applied. So let's assume that the correct answer will start by saying Wally's is a large nursery. In that case, we know two things:

(1) It likely primarily sells to commercial raspberry growers. However, that double quantifier ("likely primarily") makes it hard to know the likelihood that Johnson is a commercial grower—he certainly could be, but we aren't guaranteed he probably is.

(2) It likely guarantees its plants and, since these were diseased, these plants would violate that guarantee.

Let's see if we can find an answer that lines up with one of these inferences, with the last being the most likely.

Answer Explanation:
Most large nurseries guarantee their plants against disease. So if Wally's Plants is a large nursery, they most likely have such a guarantee. Since the plants Johnson received had a virus, they would have violated this guarantee, so this answer is correct.

Key Takeaway:
Must Be True questions generally include all information to make the inferences in the stimulus, but generally isn't always. If you note that a conditional can't apply to a given scenario, leave room for the possibility that the correct answer will provide extra information that does allow it to be applied (generally introduced with an, "If . . . ").