Difficulty: Medium
Correct Answer: None of three
Explanation:
Introduction / Context:
This question mixes “some” with two universal statements. The danger is to infer overlaps between Cars and Boxes or Pens and Jeeps without explicit compulsion.
Given Data / Assumptions:
Concept / Approach:
To prove “some X are Y,” we need a compelled intersection. To prove “No X is Y,” we need a compelled disjointness. Here, neither is forced between Cars and Boxes nor between Pens and Jeeps.
Step-by-Step Solution:
Verification / Alternative check:
Draw J as a set. Place B entirely inside J but outside C. Place C partially overlapping J (to satisfy “some C are J”) and put P inside the C area that is outside J. All premises hold; (1), (2), and (3) are false simultaneously, proving that none of the three conclusions must follow.
Why Other Options Are Wrong:
Common Pitfalls:
Assuming that two sets contained in a third must overlap each other. Subsets of a common superset can still be disjoint.
Final Answer:
None of three
Discussion & Comments