Civil Services Prep

Prelims 2022 · CSAT / Logical Reasoning · Question 75

What is the value of X in the sequence 2, 12, 36, 80, 150, X?

  1. 248
  2. 252
  3. 258
  4. 262

Answer

252

Sequence pattern: (2=1\times2), (12=2\times6), (36=3\times12), (80=4\times20), (150=5\times30). This fits (n^2(n+1)): (1^2\times2, 2^2\times3, 3^2\times4, 4^2\times5, 5^2\times6). So next term is (6^2\times7=252).

  • (a) 248: Does not fit the pattern. Incorrect.
  • (b) 252: Matches (6^2\times7). Correct.
  • (c) 258: Does not fit the pattern. Incorrect.
  • (d) 262: Does not fit the pattern. Incorrect.
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