Logic necessity (“only when”): Statement: “Only when the CM goes out, the roads are cleaned.” Pick the pair that fits the necessity correctly. (i) The roads are cleaned. (ii) The roads are dirty. (iii) The CM goes out. (iv) The CM does not go out.
Verbal Reasoning
Logical Deduction
Difficulty: Medium
Choose an option
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A(iii) (i)
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B(i) (iii)
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C(iv) (ii)
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D(iv) (i)
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ENone of these
Answer
Correct Answer: (i) (iii)
Explanation
Introduction / Context:“Only when” introduces a necessary condition. “Roads cleaned only when CM goes out” means: RoadsCleaned → CMOut.
Given Data / Assumptions:
- We do not know that CMOut is sufficient; we only know it is necessary for roads to be cleaned.
Concept / Approach:Select a pair matching the necessity direction.
Step-by-Step Solution:(i) Roads cleaned; (iii) CM goes out → consistent with RoadsCleaned → CMOut.
Verification / Alternative check:(iii)(i) treats CMOut as sufficient; the statement does not guarantee that.
Why Other Options Are Wrong:They miss the necessity direction or introduce unrelated negatives.
Common Pitfalls:Confusing necessary with sufficient conditions.
Final Answer:(i) (iii)