Example 1
Which letter comes next? H, J, L, N, ?
Answer: A) P
Each letter moves 2 places forward: N + 2 = P.
Letter Series reasoning questions for competitive exams: rules, worked examples and practice
Letter series questions follow a fixed gap between letters. Convert letters to numbers and find the gap.
Key rules and formulas
- Use A=1 … Z=26 and look at the differences.
- Gaps can be constant, increasing, or alternate between two values.
- After Z, the series wraps back to A.
- Check two different steps of the pattern before answering.
Common traps
- Not wrapping around after Z.
- Assuming a constant gap when it alternates.
Where Letter Series is asked
- RRB Group D (General Intelligence & Reasoning)
- RRB NTPC CBT 1 (General Intelligence & Reasoning)
- SSC CGL Tier 1 (General Intelligence & Reasoning)
- SSC CGL Tier 2 (General Intelligence, Reasoning & General Intelligence)
- SSC CHSL Tier 1 (General Intelligence)
Worked examples
Example 2
Which letter comes next? C, G, K, O, ?
Answer: D) S
Each letter moves 4 places forward: O + 4 = S.
Example 3
Which letter comes next? G, K, O, S, ?
Answer: B) W
Each letter moves 4 places forward: S + 4 = W.
Frequently asked questions
What is Letter Series in competitive exams?
Letter series questions follow a fixed gap between letters. Convert letters to numbers and find the gap.
Which exams ask Letter Series questions?
On MockBazaar, Letter Series questions appear in RRB Group D, RRB NTPC CBT 1, SSC CGL Tier 1, SSC CGL Tier 2, SSC CHSL Tier 1.
What is the most common mistake in Letter Series?
Not wrapping around after Z.