Identify the odd number: In 11, 8, 14, and 66, three are even (and composite), while one is an odd prime. Select the odd prime.
Verbal Reasoning
Classification
Difficulty: Easy
Choose an option
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A11
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B8
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C14
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D66
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ENone of these
Answer
Correct Answer: 11
Explanation
Introduction / Context:The majority here are even composites; the outlier is an odd prime. Distinguishing parity and primality together solves the item fast.
Given Data / Assumptions:
- Set: 11, 8, 14, 66.
- Even numbers greater than 2 are composite.
Concept / Approach:Check parity first, then apply quick prime tests to any odd candidates.
Step-by-Step Solution:
8 → even composite (2 * 2 * 2).14 → even composite (2 * 7).66 → even composite (2 * 3 * 11).11 → odd and not divisible by 3 or 5 → prime.Verification / Alternative check:Trial division up to sqrt(11) confirms its primality. Others have obvious factors of 2.
Why Other Options Are Wrong:They are even composites, consistent with the majority property.
Common Pitfalls:Confusing “odd” with “composite”; many odd numbers are prime.
Final Answer:11 is the odd prime and the correct choice.