CAT 2021 Slot 2 QA Q20 Progressions & Series

Question 20 of the Quantitative Ability (QA) section, CAT 2021 Slot 2, with CAT's official answer.

For a sequence of real numbers x1, x2, ..., xn, if x1 - x2 + x3 - ... + (-1)n + 1xn = n2 + 2n for all natural numbers n, then the sum x49 + x50 equals
  1. A
    2
  2. B
    -2
  3. C
    200
  4. D
    -200

Answer: (B) -2 Progressions & Series MCQ

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