Odd one out
Ten reasoning questions, each marked as you answer.
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Which one does not belong with the others?
Answer and working
Answer A
36, 169, 144 are perfect squares; 79 is not. The odd one is 79.
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Which one does not belong with the others?
Answer and working
Answer B
1000, 125, 8 are cubes; 225 is a square, not a cube. The odd one is 225.
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Which one does not belong with the others?
Answer and working
Answer B
53, 11, 43 are prime; 51 = 3 × 17. The odd one is 51.
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Which one does not belong with the others?
Answer and working
Answer C
In the others the letters are 3 apart (GJM); in ADH the last gap is 4. The odd one is ADH.
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Which one does not belong with the others?
Answer and working
Answer C
In the others the second number is n² of the first; 4 : 15 breaks it. The odd one is 4 : 15.
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Which one does not belong with the others?
Answer and working
Answer A
73, 61, 17 are prime; 33 = 3 × 11. The odd one is 33.
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Which one does not belong with the others?
Answer and working
Answer B
17, 23, 61 are prime; 51 = 3 × 17. The odd one is 51.
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Which one does not belong with the others?
Answer and working
Answer A
81, 27, 90 are multiples of 9; 74 is not. The odd one is 74.
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Which one does not belong with the others?
Answer and working
Answer D
23, 11, 61 are prime; 91 = 7 × 13. The odd one is 91.
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Which one does not belong with the others?
Answer and working
Answer D
84, 56, 28 are multiples of 7; 81 is not. The odd one is 81.
More reasoning: Number and letter series, Coding and decoding, Analogies, Blood relations, Direction sense, Seating in a row.