Multiple choice

In the following number series find the wrong term. 12 7 8 13 27 69 206.5

  1. 7

  2. 8

  3. 27

  4. 69

  5. 13

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Find the pattern: 12 × 0.5 + 1 = 7, 7 × 1 + 1 = 8, 8 × 1.5 + 1 = 13, 13 × 2 + 1 = 27, 27 × 2.5 + 1 = 68.5 (not 69), 69 × 3 + 1 = 208 (not 206.5). The pattern is: multiply by increasing halves (0.5, 1, 1.5, 2, 2.5, 3...) and add 1. Checking: 27 × 2.5 + 1 = 67.5 + 1 = 68.5, but the series has 69. So 69 is the wrong term - it should be 68.5. Option D is correct.