Alphabet Series

Subject: Mental Ability | Frequency: 1-2 questions per APPSC paper | Time: 30-45 sec/question

Introduction

Alphabet series questions give a sequence of letters or letter groups following a hidden pattern. You must find the next term or the missing term. The EJOTY technique (E=5, J=10, O=15, T=20, Y=25) converts slow counting into instant position lookup and is the single most important skill for this topic.

Core Method

Convert letters to position numbers — A=1, B=2... Z=26
Use EJOTY as anchor points — E=5, J=10, O=15, T=20, Y=25
Calculate gaps between consecutive terms
Check for constant gap — +1, +2, +3, etc.
Check for increasing/decreasing gap — +1, +2, +3 or +2, +4, +6
Check for alternating patterns — separate odd/even positions
For multi-letter groups — analyze each position independently
Apply the pattern to predict the next term

EJOTY Quick Reference

A  B  C  D  E  F  G  H  I  J  K  L  M
1  2  3  4  5  6  7  8  9  10 11 12 13

N  O  P  Q  R  S  T  U  V  W  X  Y  Z
14 15 16 17 18 19 20 21 22 23 24 25 26

Opposite pairs (sum = 27): A-Z, B-Y, C-X, D-W, E-V, F-U, G-T, H-S, I-R, J-Q, K-P, L-O, M-N

Worked Examples — Easy

Q1: B, D, F, H, ?

Positions: 2, 4, 6, 8 → gap = +2
Next: 10 = J

Q2: Z, W, T, Q, ?

Positions: 26, 23, 20, 17 → gap = -3
Next: 14 = N

Q3: A, E, I, M, ?

Positions: 1, 5, 9, 13 → gap = +4
Next: 17 = Q

Worked Examples — Medium

Q4: AZ, BY, CX, DW, ?

First letters: A, B, C, D → next: E
Second letters: Z, Y, X, W → next: V
Answer: EV

Q5: A, B, D, G, K, ?

Positions: 1, 2, 4, 7, 11 → gaps: +1, +2, +3, +4
Next gap = +5 → 11 + 5 = 16 = P

Q6: AB, EF, IJ, MN, ?

Starting positions: 1, 5, 9, 13 → gap = +4
Next start: 17 = Q → Answer: QR

Worked Examples — Hard

Q7: B, E, I, N, T, ?

Positions: 2, 5, 9, 14, 20 → gaps: +3, +4, +5, +6
Next gap = +7 → 20 + 7 = 27 → wraps to 27 - 26 = 1 = A

Q8: DHL, PTX, BFJ, ?

D=4, H=8, L=12: within group gap +4
P=16, T=20, X=24: within group gap +4
B=28mod26=2, F=32mod26=6, J=36mod26=10: within group gap +4
Next: 40mod26=14=N, 44mod26=18=R, 48mod26=22=V
Answer: NRV

Q9: Complete: a_bcc_aab_cca_bbcc

Try repeating group "aabbcc":
aabbcc | aabbcc | aabbcc
Missing letters: a, a, b, a

Shortcuts & Tricks

Shortcut	When to Use
EJOTY memorization	E=5, J=10, O=15, T=20, Y=25 — instant position lookup
Opposite letter = 27 - n	A<->Z, B<->Y, C<->X — instant reverse finding
Mod 26 for wrapping	When position > 26, subtract 26 to wrap around
Group pattern isolation	In multi-letter groups, analyze each position separately
Continuous series: try 3 or 4-letter repeats	Most common repeat lengths

Common Mistakes

Miscounting letter positions — especially in K-Z range; use EJOTY anchors
Not handling wrap-around — after Z comes A (position 27 = 1)
Confusing multi-letter group patterns — analyze each position in the group independently
Missing alternating sub-series — not splitting odd/even indexed terms
Rushing continuous series — these need patient grouping; try different repeat lengths

Exam Strategy

Memorize EJOTY cold — it converts slow counting into instant lookup
APPSC keeps difficulty at easy-to-medium
Simple gap series and double-letter groups are the most common types
Time: 30-45 seconds per question
For continuous pattern series (a_b_c type), try 3-letter, 4-letter, 5-letter, and 6-letter repeating groups

Practice Questions

C, F, I, L, ? → gap +3 → O (15)
Z, X, V, T, ? → gap -2 → R (18)
AZ, CX, EV, GT, ? → first +2, second -2 → IR (9, 18)
A, C, F, J, O, ? → gaps +2, +3, +4, +5 → next +6 → 15+6=21 → U
ACE, FHJ, KMO, ? → start +5, within +2 → P, R, T → PRT

Key Terms / Formulas

Term	Meaning
EJOTY	Position anchors: E=5, J=10, O=15, T=20, Y=25
Position value	A=1, B=2 ... Z=26
Opposite pair	Two letters whose positions sum to 27
Wrap-around	Position > 26 → subtract 26 (Z wraps to A)
Alternating series	Two interleaved sub-series at odd/even positions