Identify the odd term in the list: 1, 4, 9, 16, 23, 25, 36.
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A9
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B23
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C25
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D36
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ENone of these
Answer
Correct Answer: 23
Explanation
Introduction / Context:The sequence is dominated by perfect squares with a single intrusion. Recognizing squares at a glance is the fastest approach to identifying the non-matching term.
Given Data / Assumptions:
- Squares present: 1(=1^2), 4(=2^2), 9(=3^2), 16(=4^2), 25(=5^2), 36(=6^2)
- 23 is not a perfect square
Concept / Approach:Confirm each as a square or not, and pick the sole non-square as the odd item.
Step-by-Step Solution:Check 23: it lies between 16 and 25; √23 ≈ 4.796, not integerAll others equal n^2 for integer nHence, 23 is the odd term
Verification / Alternative check:Prime factorization also shows 23 is prime and not a square of any integer.
Why Other Options Are Wrong:9/25/36 are perfect squares and belong in the square set.
Common Pitfalls:Confusing 25 with 5^3 (it is 5^2); mixing cube recognition with square recognition.
Final Answer:23