UPSC Prelims 2019·CSAT·Logical Reasoning·Series and Sequences

What is X in the sequence 132, 129, 124, 117, 106, 93, X ?

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Last updated 23 May 2026, 3:31 pm IST
  1. A74
  2. B75
  3. C76Correct
  4. D77

Explanation

To find the value of X, we need to determine the difference between consecutive numbers in the sequence. 132 minus 129 equals 3. 129 minus 124 equals 5. 124 minus 117 equals 7. 117 minus 106 equals 11. 106 minus 93 equals 13. The sequence of differences is 3, 5, 7, 11, 13. These are consecutive prime numbers starting from 3. The next prime number after 13 is 17. Therefore, to find X, we subtract 17 from the last number in the sequence. 93 minus 17 equals 76. The correct answer is 76.
Logical Reasoning: What is X in the sequence 132, 129, 124, 117, 106, 93, X ?

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