SSC CHSL 2024 · PYQ · Number Series · medium
What should come in place of the question mark (?) in the given series?
129, 128, 124, 115, 99, ?
- A.72
- B.74✓ Correct
- C.71
- D.73
The differences are: 1, 4, 9, 16 — perfect squares (1², 2², 3², 4²). So the next difference should be 5² = 25. Therefore ? = 99 – 25 = 74.
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