Logical reasoning PrepTest 125 · Section 2 · Question 20

Incorrect. The statement about thorough cleaning is relative—"as thoroughly cleaned"—so we can't make this jump to an absolute phrase ("not been thoroughly cleaned").

Incorrect. There's no discussion of foods that can't be packaged in recycled Styrofoam—this answer is too strong.

Incorrect. The argument never dives into reasons that the Styrofoam needs cleaning other than that it needs to be clean—whether that's because it went through the trash first or because it came into contact with food or for some other reason is unknown.

Incorrect. The argument never discusses how common recycled Styrofoam containers are generally or for any specific application, so this answer is out of scope.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Egg shells protect the actual food from contact, so used Styrofoam doesn't have to be washed as thoroughly when being recycled into egg cartons, making them among the easiest recycled Styrofoam containers to make.

Answer Anticipation:
The stimulus here has a few elements that commonly lead to inferences in Must Be True questions.

First, the argument compares recycled Styrofoam egg cartons to other recycled Styrofoam containers, noting that they're generally easier to make and need to be washed less thoroughly.

Second, the argument presents a reason for why this is the case—egg shells prevent the actual food from coming into contact with the container.

Since the latter details is the reason for the former details, we can make an inference by combining them—it must be the case that the food in other types of food containers that aren't as easy to make and need to be more thoroughly cleaned does come into contact with those food products, thus necessitating those precautions.

Answer Explanation:
The argument notes that the egg shells keep the Styrofoam from touching the actual food as an explanation for why egg containers are different from other types of food containers. Since that is the reason given for a difference, other types of food must be different in this regard—they must come into contact with the Styrofoam container (explaining why they need to be more thoroughly cleaned).

Key Takeaway:
Causality and comparisons are two common stimulus elements that lead to inferences in Must Be True questions, so note them when they appear.