Home › Exam notes › SSC CGL › Alphabet & Alphanumeric Series

Alphabet & Alphanumeric Series

General Intelligence & Reasoning · Series (Number & Alphabet)

Useful for: SSC CGL

हिंदी में पढ़ें

Overview

Letter and alphanumeric series move through the alphabet with fixed or changing gaps, sometimes combined with numbers.

Key points

Use positions: B, E, H, K → 2, 5, 8, 11 (+3).
Gaps may increase: A, B, D, G, K (+1, +2, +3, +4).
Alphanumeric terms like A2, C4, E6 combine a letter series and a number series.
Reverse alphabet series move backwards (Z, X, V…).
Missing-letter strings repeat a block: abc_abc_ → find the repeating unit.

Explanation

Split each term into parts and solve each part separately.
For repeating-string questions, count the block length first.
Wrap-around after Z is rare in SSC but possible.
Opposite-letter rules (sum 27) may appear in pairs.

Step by step

Convert to positions.
Find the gap pattern.
Convert back to letters.

Examples

B, E, H, K, ? → +3 → N.
A, B, D, G, K, ? → +1, +2, +3, +4, +5 → P.
A2, C4, E6, G8, ? → letters +2, numbers +2 → I10.

Traps and advanced points

Trap: Counting positions incorrectly.
Trap: Solving letters and numbers as one series.
Trap: Missing the growing gap.

Quick revision

Positions first.
Split letters and numbers.
Find the repeating block.

Practice MCQs

Find the next term: A, C, E, G, ?
1. H
2. J
3. K
4. I
Read chapter notes · Similar questions
Show answer
Answer: (d) I. Har letter +2 gap (A→C→E→G).
Find the next term: Z, X, V, T, ?
1. U
2. Q
3. R
4. S
Read chapter notes · Similar questions
Show answer
Answer: (c) R. Reverse order, -2 gap (Z→X→V→T).
Find the missing term: B, D, G, K, ?
1. P
2. O
3. N
4. Q
Read chapter notes · Similar questions
Show answer
Answer: (a) P. Gaps increasing: B(+2)D(+3)G(+4)K(+5)P.
Complete: A1, C3, E5, G7, ?
1. H9
2. J9
3. I9
4. I8
Read chapter notes · Similar questions
Show answer
Answer: (c) I9. Letters +2 (A,C,E,G,I), numbers odd +2 (1,3,5,7,9).
Find the next term: AZ, BY, CX, ?
1. DV
2. EW
3. DX
4. DW
Read chapter notes · Similar questions
Show answer
Answer: (d) DW. First letter +1 (A,B,C,D), second letter -1 (Z,Y,X,W).
Find the missing term: AB, DE, GH, JK, ?
1. MO
2. NO
3. MN
4. LM
Read chapter notes · Similar questions
Show answer
Answer: (c) MN. Each pair jumps +3 from previous pair's start (A,D,G,J,M) with consecutive second letter.
Find the next term: C, F, I, L, ?
1. M
2. P
3. O
4. N
Read chapter notes · Similar questions
Show answer
Answer: (c) O. Gap +3 (C→F→I→L).
Complete: Z1, Y2, X3, W4, ?
1. V4
2. W5
3. V5
4. U5
Read chapter notes · Similar questions
Show answer
Answer: (c) V5. Letters reverse (Z,Y,X,W,V), numbers +1 (1,2,3,4,5).
Find the missing term: B2, D4, F6, H8, ?
1. J10
2. I10
3. J9
4. K10
Read chapter notes · Similar questions
Show answer
Answer: (a) J10. Letters +2 (B,D,F,H,J), numbers = letter position pattern (2,4,6,8,10).
Find the next term: AZ, CX, EV, ?
1. FT
2. GT
3. GU
4. HT
Read chapter notes · Similar questions
Show answer
Answer: (b) GT. First letter +2 (A,C,E,G), second letter -2 (Z,X,V,T).