Multiple choice

Find the wrong term in the givens series. 9, 13, 21, 37, 69, 132, 261

  1. 21

  2. 37

  3. 69

  4. 132
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D Correct answer
Explanation

Pattern: x_n = 2 * x_{n-1} - 5. 9*2-5=13, 13*2-5=21, 21*2-5=37, 37*2-5=69, 69*2-5=133 (not 132).

AI explanation

We calculate the differences between the consecutive terms of the series. The differences are 4, 8, 16, 32 and 63, which should form a doubling pattern, but 69 plus 64 equals 133 instead of the given 132. This makes 132 the incorrect term in the sequence.

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