Multiple choice

Find the wrong term in sequence : 11, 21, 43, 85, 171, 343

  1. 21

  2. 85

  3. 171

  4. 343
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D Correct answer
AI explanation

The pattern follows the logic of multiplying by 2 and then subtracting 1, or multiplying by 2 and adding 1, alternately. Applying this to 11 gives 21 (11 times 2 minus 1), then 43 (21 times 2 plus 1), then 85 (43 times 2 minus 1), and 171 (85 times 2 plus 1). Following this rule, the next term must be 341 (171 times 2 minus 1), so 343 is the wrong term in the sequence.

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