Syllogism — Premises: All hens are cocks. No cock is black. Conclusions: I) All cocks are hens. II) No hen is black.
Verbal Reasoning
Syllogism
Difficulty: Easy
Choose an option
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AOnly conclusion I is valid
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BOnly conclusion II is valid
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CBoth the conclusions are valid
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DBoth the conclusions are invalid
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ENone of these
Answer
Correct Answer: Only conclusion II is valid
Explanation
Introduction / Context:This mixes a universal inclusion with a universal exclusion. We test each conclusion cautiously for direction and scope.
Given Data / Assumptions:
- Hens ⊆ Cocks.
- Cocks ∩ Black = ∅.
Concept / Approach:From Hens ⊆ Cocks and no Cock is Black, we infer Hens ∩ Black = ∅, i.e., no hen is black (II). The first conclusion reverses inclusion and is not supported.
Step-by-Step Solution:
Step 1: Substitute: any hen is a cock.Step 2: Since no cock is black, that hen cannot be black.Step 3: Hence II holds. I fails because 'All cocks are hens' is the converse and need not be true.Verification / Alternative check:Model where some cocks are not hens satisfies premises but falsifies I.
Why Other Options Are Wrong:Any option including I treats converse as valid; it is not.
Common Pitfalls:Confusing subset with set equality.
Final Answer:Only conclusion II is valid.