Complete the Number Series: 5, 11, 23, 47, 95, ?

Question

Complete the Number Series: 5, 11, 23, 47, 95, ?

1. A. 189
2. B. 191 (Correct answer)
3. C. 187
4. D. 193

Correct Answer

Option B — 191

Detailed Solution & Explanation

The correct answer is 191.

Key Points

• This number series follows a multiply-and-add rule.
• Series: 5, 11, 23, 47, 95, ?
• 5 × 2 + 1 = 11
• 11 × 2 + 1 = 23
• 23 × 2 + 1 = 47
• 47 × 2 + 1 = 95
• 95 × 2 + 1 = 191
• Each term is the previous term doubled, plus 1, so the next number is 191.
• when terms roughly double each step, test the rule ×2 + constant.
• The constant is found from the first pair (11 − 2×5 = 1), then verified on every later pair.

Exam Tip

• note the near-look-alike 189 in the options — it equals 95×2−1, a common distractor.
• Always apply the exact rule (×2 +1) rather than approximating.