UPSC Prelims 2023·CSAT·Logical Reasoning·Coding Decoding

Choose the group which is different from the others:

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Last updated 23 May 2026, 3:31 pm IST
  1. A17, 37, 47, 97
  2. B31, 41, 53, 67
  3. C71, 73, 79, 83
  4. D83, 89, 91, 97Correct

Explanation

The distinguishing factor is whether all numbers in the group are prime. A) 17, 37, 47, 97: All are prime numbers. B) 31, 41, 53, 67: All are prime numbers. C) 71, 73, 79, 83: All are prime numbers. D) 83, 89, 91, 97: This group contains 91, which is a composite number (7 x 13 = 91). The other numbers (83, 89, 97) are prime. Therefore, group D is different because it is the only group that contains a composite number.
Logical Reasoning: Choose the group which is different from the others

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