Syllogism — Premises: Some teachers are students. All students are girls. Conclusions: (I) All teachers are girls. (II) Some girls are teachers. (III) Some girls are students. (IV) All students are teachers.
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AOnly (I) follows
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BOnly (I), (II), and (III) follow
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COnly (II) and (III) follow
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DAll follow
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ENone of these
Answer
Correct Answer: Only (II) and (III) follow
Explanation
Introduction / Context:We combine one existential and one universal premise and check which conclusions are necessary.
Given Data / Assumptions:
- Some Teachers are Students.
- All Students are Girls.
Concept / Approach:Let T = Teachers, S = Students, G = Girls. From 'Some T are S' and 'S ⊆ G', we infer (II) Some girls are teachers (those teacher-students are girls) and (III) Some girls are students (since some students exist). The universal claims (I) and (IV) are not supported.
Step-by-Step Solution:
Step 1: Pick x with x ∈ T ∩ S (from the 'some' statement).Step 2: From S ⊆ G, x ∈ G, so x ∈ G ∩ T — validates (II).Step 3: The existence of x ∈ S implies at least one student exists; since S ⊆ G, (III) holds.Step 4: There is no basis for 'All teachers are girls' (I) nor 'All students are teachers' (IV).Verification / Alternative check:Construct a model with many teachers not students and many girls not students; (II) and (III) remain forced while (I) and (IV) fail.
Why Other Options Are Wrong:Options including (I) or (IV) assert unsupported universals.
Common Pitfalls:Overgeneralizing from existence to universals; keep directions of subset relations straight.
Final Answer:Only (II) and (III) follow.