Multiple choice

Directions: Find the wrong number in the following number series. 8, 31, 79, 169, 353, 721, 1457

  1. 1457

  2. 353

  3. 79

  4. 721

  5. 31
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The pattern is: 8*2+15=31, 31*2+17=79, 79*2+11=169. The pattern of additions is 15, 17, 19, 21... If we use 15, 17, 19, 21, 23, 25: 8*2+15=31, 31*2+17=79, 79*2+19=177. The number 79 is the first point of deviation if the pattern is *2 + (odd numbers).

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