Question

In each of the following number series, the wrong number is given, find out that number.

11, 21, 42, 77, 150, 295, 584
1. 77
2. 11
3. 21
4. 42
5. 584

Answer 1

Correct Answer - Option 4 : 42

Calculation:

11 × 2 – 1 = 21

21 × 2 – 2 = 40

40 × 2 – 3 = 77

77 × 2 – 4 = 150

150 × 2 – 5 = 295

295 × 2 – 6 = 584

∴ Wrong number in the series is 42.