Logical reasoning PrepTest 137 · Section 3 · Question 3

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
not Building permit by 2/1 AND not Some activities finished early → not Library completed on schedule
not Building permit by 2/1
Therefore: not Library completed on schedule

Answer Anticipation:
Strengthen with Sufficient Premise questions frequently feature conditional logic, so as soon as you saw that keyword starting this stimulus off—"Unless"—you should have shifted into diagramming gear.

This first statement is a little complex. There are two ways to diagram "Unless"—you can treat it as the necessary conditions and negate the sufficient, or you can treat it as "if not." We opted for the latter here, but be careful! "If not" means that it introduces the sufficient condition, but you have to negate it. The statement it modifies here is an OR statement, which becomes an AND statement when negated—as our diagram shows.

If you get that first statement diagrammed, then we can see that there are two sufficient conditions, both of which need to be established (AND) before we can conclude the necessary condition using it. However, the premise only establishes one of the two conditions—so in order to justify the conclusion, the correct answer should establish the other. Let's find an answer stating that other activities necessary for the construction of the new library can't be completed in less time than planned.

Answer Explanation:
This answer establishes that none of these other necessary activities can be completed in less time than expected, so it meets the second sufficient condition and allows it to be triggered, justifying the necessary condition/conclusion.

Key Takeaway:
Strengthen with Sufficient Premise questions frequently feature conditional logic. Therefore, when you're in this question type and you see conditional language, you should start diagramming immediately!

Incorrect. First, officials claiming something doesn't make it true. Second, they claim only that it "probably" won't be completed on schedule, which is less certain than the conclusion and thus almost certainly not strong enough to justify it.

Incorrect. This answer allows us to conclude something the argument already established—that the permis won't be obtained by 2/1. Since it establishes something we already knew, it adds nothing to the argument.

Incorrect. This answer may explain the delays around the building permit, but the argument already established that the building permit won't be obtained on time, so this doesn't add anything to the argument.

Incorrect. Like several other answers, this answer backs up the problems with not obtaining the building permit on time. However, there was another avenue to finishing on time—taking less time on some other parts of the project. Without ruling that out, no answer is going to justify the conclusion.