Difficulty: Easy
Correct Answer: 21
Explanation:
Introduction / Context:Another parity-based odd-one-out: scan the list for a single odd among evens or vice versa. Rapid parity checks are often the fastest way to resolve such items in competitive exams.
Given Data / Assumptions:
Concept / Approach:Since only 21 does not share even parity with the rest, it is the outlier by parity classification.
Step-by-Step Solution:Check parity: 10(E), 14(E), 16(E), 18(E), 21(O), 24(E), 26(E)Hence, 21 is the odd term
Verification / Alternative check:Other simple rules (like divisibility by 3) would exclude multiple terms; parity yields a unique odd entry here.
Why Other Options Are Wrong:26/24/18 are even and thus align with the dominant pattern.
Common Pitfalls:Looking for arithmetic sequences or factor patterns when an obvious parity cue suffices.
Final Answer:21
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