Logical reasoning PrepTest 101 · Section 3 · Question 21

Correct. Argument or Facts:
Argument

Valid or Flawed:
Valid

Question Type:
Parallel Reasoning

Stimulus Summary:
Relationship - Millville electricity use is directly proportional to peak humidity
Comparison - This August has higher average peak humidity than last August
Conclusion - This August has more energy consumption than last August

Answer Anticipation:
This argument relies heavily on comparisons. It starts by establishing a directly proportional relationship between two things—peak humidity, and energy use. From there, it compares the peak humidity in two months, and then validly concludes that the month with higher peak humidity also had higher energy use, based on the directly proportional relationship already established.

Let's find an answer that similarly establishes a directly proportional relationship, brings up a comparison that plays into that relationship, and then validly concludes a comparison between the other element in the relationship.

Answer Explanation:
This argument establishes a directly proportional relationship between art supply use and number of students. It then compares the number of students in two years, and concludes a valid comparison between the art supply use each year. That's the same reasoning as the stimulus, so this is the correct answer.

Key Takeaway:
Comparative logic is one of the most common types of logic on the exam. That said, there are specific types of comparisons that you should be aware of—including directly proportional relationships. These are very strong comparative relationships, so pay attention when one shows up!

Incorrect. This argument establishes a directly proportional relationship between number of courses and number of enrolled students. However, the next premise doesn't bring up a difference in one of these elements between two time periods—it says that a subset of one of them stays the same between time periods.

Incorrect. This argument establishes a directly proportional relationship between number of new students and amount of advertising. However, then it concludes that something is required to increase advertising—it doesn't compare either element over two time periods.

Incorrect. This argument establishes a directly proportional relationship between fees paid and number of classes taken. However, it then analyzes something that doesn't show up in this relationship—number of students enrolled—and so is invalid.

Incorrect. This argument establishes a directly proportional relationship, but it's between one element and two others. Since that's a different type of relationship than in the stimulus, we can rule this out.