Railways PYQCBT 2 2017

RRB NTPC · Question 26

A number series is given below with one number missing, shown by a "?". Choose from the options the correct alternative that will fit the pattern of the series. 4, 9, 19, ?, 79, 159

  1. 59

  2. 33

  3. 39

  4. 34

Show answer & explanation

Answer: (C) 39

Explanation

Each term is double the previous plus 1: 4 → 9 → 19 → 39 → 79 → 159.