Multiple choice

Find the wrong number in the following number series. 4866, 2432, 1218, 610, 306, 154, 78

  1. 4866

  2. 78

  3. 2432

  4. 154

  5. 610

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

The pattern in the series is: each term = (previous term)/2 - 1. Starting from 4866: 4866/2 - 1 = 2433 (but 2432 is given, which is 1 less). For 2432: 2432/2 - 1 = 1215 (but 1218 is given, which is 3 more). From 1218 onwards, the pattern fits perfectly: 1218/2 - 1 = 609 (close to 610), 610/2 - 1 = 304 (close to 306), 306/2 - 1 = 152 (close to 154), 154/2 - 1 = 76 (close to 78). The number 2432 breaks the pattern as it creates an irregularity that propagates through the series.