Difficulty: Medium
Correct Answer: None follows
Explanation:
Introduction / Context:
This is a classic trap: several existential (“some”) premises are given, each possibly about different elements of the sets. The test is whether you can resist “connecting the dots” without a premise that forces the same individuals to serve in each overlap.
Given Data / Assumptions:
Concept / Approach:
From “some A are B” and “some B are C,” you cannot infer “some A are C” unless there is information that ties the same members across the overlaps. Each “some” could refer to a different subset of B. Thus, none of the cross-bridge conclusions is forced.
Step-by-Step Solution:
Verification / Alternative check:
Create a model where the overlaps are pairwise disjoint: one item is a pen-pencil only, a second is a pencil-eraser only, and a third is an eraser-sharpener only. All premises hold, but none of I–III is satisfied, proving that no listed conclusion is necessary.
Why Other Options Are Wrong:
Common Pitfalls:
Illicitly chaining existential statements as if they were universal inclusions; forgetting that “some” can refer to different elements in each premise.
Final Answer:
None follows.
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