Multiple choice

Directions: In the following number series, one of the numbers is wrong in the sense that it does not belong to the series. Find that number. 3, 7, 15, 27, 63, 127, 255

  1. 7

  2. 15

  3. 27

  4. 63
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The series follows the pattern 2^n - 1. 2^2-1=3, 2^3-1=7, 2^4-1=15, 2^5-1=31, 2^6-1=63, 2^7-1=127, 2^8-1=255. The number 27 is incorrect; it should be 31.

Keep practicing — related questions