Syllogism — Premises: All hens are cocks. No cock is black. Conclusions: I) All cocks are hens. II) No hen is black.

Difficulty: Easy

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.

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