Logical reasoning PrepTest 127 · Section 3 · Question 16

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Sufficient Premise

Stimulus Summary:
not Trust → not Meaningful emotional human connection
not Meaningful emotional human connection → Feel isolated
Therefore - Happiness → Trust

Answer Anticipation:
There are two common trends in Strengthen with Sufficient Premise questions that we see in this question, both of which will let us quickly get to the correct answer. The first is that it features a series of conditional statements, so we know we'll be chaining them together to find a gap. The second is a new term in the conclusion ("happiness"), so we'll need to connect that term to the conditional chain from the premises.

If you'll note our conditional premises, you'll see that we diagrammed them by treating "without" as "if not"—if you diagrammed it using another method, then you should have ended up with the contrapositive. As we'll see, this'll actually make the question easier, but let's work with what we have! Also, note the conclusion—something that is "essential" for something else is necessary for that thing, so since the conclusion is that trust is essential to happiness, we end up with the conditional as summarized.

Those two conditional chain together, so we can rewrite it as:
not Trust → not Meaningful connection → Feel isolated

To get it to line up with the conclusion, where Trust is a necessary condition, we need to take the contrapositive:
not Feel isolated → Meaningful connection → Trust

And, from here, we can see that to justify the conclusion, we need to connect Happiness to the beginning of this chain in order to get it to lead to Trust (and its contrapositive):
Happiness → not Feel isolated
Feel isolated → not Happiness

Answer Explanation:
Feel isolated → not Happiness. This is the answer we anticipated (the contrapositive), and it connects the new term in the conclusion to the chain in the premises, justifying that conclusion.

Key Takeaway:
For Strengthen with Sufficient Premise questions with multiple conditional statements, you'll likely need to chain those premises together and find the missing link between them, or between them and the conclusion. When there's a new term in the conclusion, that term will need to be connected to a premise.

Incorrect. First, this answer treats happiness as a necessary condition, whereas it's a sufficient one in the stimulus. Second, it establishes that someone can feel happy—not that they will. Compare this to (A), where the phrasing led to happiness being impossible in a given situation. A possibility isn't conditional; certainty is.

Incorrect. not Feel isolated → Trust. This answer is already established in the premises when they're chained together.

Incorrect. This answer is too weak. The conclusion is conditional, and this answer just raises something as possible ("At least some").

Incorrect. Trust → Meaningful emotional connection. This answer is a reversal/negation of a premise, so it doesn't connect the premises to the conclusion.