Question

What should come in place of the question mark (?) in the following number series?

10, 19, 37, ?, 145, 289

1. 71
2. 72
3. 73
4. 74
5. 75

Answer 1

Correct Answer - Option 3 : 73

Given:

10, 19, 37, ?, 145, 289

Calculation:

The logic follows here is:

10 × 2 - 1 = 20 - 1 = 19

19 × 2 - 1 = 38 - 1 = 37

145 × 2 - 1 = 290 - 1 = 289

By observing the pattern, we can write

37 × 2 - 1 = ?

⇒ 74 - 1 = ?

⇒ ? = 73

∴ 73 should come in place of the question mark (?).