Classification – Odd one out (numeric pair rule) Each option is a pair a–b. Exactly one pair satisfies b = 2a. Identify the pair that follows doubling; it is the odd one out with respect to the others.
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A12-28
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B14-82
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C23-64
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D36-72
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ENone of these
Answer
Correct Answer: 36-72
Explanation
Introduction / Context:Pair-classification items often hide a simple arithmetic mapping from the first member to the second. Here we test for the doubling rule b = 2a. The skill is to check each option consistently and spot the single conforming (or non-conforming) case.
Given Data / Assumptions:
- Pairs: 12–28, 14–82, 23–64, 36–72
- We examine whether b equals 2a.
Concept / Approach:Compute 2a and compare to b in each pair. If exactly one pair matches, that pair is the odd one out relative to the rest (which do not match).
Step-by-Step Solution:For 12–28: 2 * 12 = 24 ≠ 28 → no.For 14–82: 2 * 14 = 28 ≠ 82 → no.For 23–64: 2 * 23 = 46 ≠ 64 → no.For 36–72: 2 * 36 = 72 → yes (unique).
Verification / Alternative check:If you try other plausible mappings (sum of digits, product, etc.), none yields a unique consistent rule across three choices. The clean doubling property isolates only 36–72.
Why Other Options Are Wrong:
- 12–28 → not double.
- 14–82 → not double.
- 23–64 → not double.
- None of these → one pair cleanly follows doubling (36–72).
Common Pitfalls:Overfitting a complicated mapping to force matches on multiple pairs. The test favors a simple, uniquely identifying rule.
Final Answer:36-72