Logical reasoning PrepTest 122 · Section 4 · Question 14

Incorrect. There's no discussion of how long the changes to the flight controls take, in either the new or the old planes. This answer is out of scope.

Incorrect. The stimulus does note that cross-checks are valuable, and the crew needs to do these checks verbally more frequently in new planes. However, it never states that these verbal check-ins are the "most valuable" means available—there could be other, more valuable means of doing so.

Incorrect. The stimulus notes that the modern planes require verbal check-ins "much more frequently," suggesting that the old planes required at least some level of verbal check-in.

Incorrect. The stimulus notes that the modern planes have a control panel that makes observing other changes "harder to observe," not impossible to observe, as this answer choice states.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Must Be True

Stimulus Summary:
Old planes - The design allows any changes in flight controls made by one crew member to be immediately reviewed by others
New planes - The design doesn't allow these valuable cross-checks
Therefore - In new planes, the crew has to verbally let others know of changes more frequently

Answer Anticipation:
This stimulus very much reads as another question type—it has an argument, which isn't usually associated with a Must Be True question. But it still is a Must Be True question, so we should treat all statements in the stimulus as true (including the conclusion) and see which answer is most strongly supported by them.

This stimulus features two elements that tend to lead to inferences. The first is that old and new planes are compared, both in their functionality and what the crew has to do in them. The old planes automatically informed all crew of changes in flight controls made by anyone, but the new planes don't. And the old planes required fewer verbal check-ins than the new ones, driven by this difference. The fact that the change to the control panel "result[ed]" in the increased need for verbal communication is a causal relationship, which is the second element that can lead to an inference.

However, since these statements don't build with other statements other than how we already noted, it's hard to anticipate something specific. Let's head to the answers looking for one that aligns with these statements we identified, or draws a weak generalization based on this single situation.

Answer Explanation:
The decreased ability to use the control panel to check in on changes made by other members of the crew has "result[ed]" in an increased need to check in verbally. Since the stimulus establishes that making one means of performing cross-checks harder resulted in verbal check-ins being needed more frequently, this answer is supported and is thus correct.

Key Takeaway:
Look for linking phrases in Must Be True questions that are more argument-based. Here, noting that the increase in need for verbal check-ins was "a result" of a change allowed us to pick an answer that included causality.