Why this topic matters · 7 min read
Alphabet Test is a high-frequency Reasoning topic in SSC CGL Tier 1 (appears 1-2 questions per paper). Tests your ability to recall letter positions, reverse sequences, and spot coding patterns. Weightage: ~2-3% of Reasoning. Speed matters — these questions should take 30-45 seconds each. Mostly straightforward if you memorize the position trick; errors happen when candidates confuse forward/reverse or miscalculate gaps.
Letter Position in Alphabet
Every letter has a fixed position: A=1, B=2, ... Z=26. SSC tests this by asking 'which letter is at position X' or 'what is the position of letter Y'. The reverse is equally important: Z=26, Y=25, ... A=1 (counting backward). Most candidates know A-M (1-13) but struggle with N-Z (14-26). A quick trick: any letter's reverse position = 27 minus its forward position.
- Forward: A=1, B=2, C=3... M=13, N=14... Z=26
- Reverse: Z=1, Y=2, X=3... N=14, M=13... A=26
- Reverse position formula: 27 - (forward position)
- Middle letter is M (13th) — use this as anchor
- Common error: confusing position 13 (M) and 14 (N)
Key formulas
Reverse Position
Reverse Position = 27 - Forward Position
When: When asked 'what is the position from the right' or 'reverse alphabet'
Worked examples
Q: What is the position of letter G from the right? A: G is 7th from left. From right = 27 - 7 = 20th.
Q: Which letter is 15th from the left? A: 15th = O (since A=1, so 15th = O).
Sequence & Gap Problems
These ask: 'How many letters are between X and Y?' or 'Which letter comes after a certain pattern?' The trick is to count the gap, not the letters themselves. If asked 'letters between A and D', count B and C = 2 letters (not 3). Gap = (position of second letter) - (position of first letter) - 1.
- Gap between two letters = difference in positions minus 1
- Example: Between C (3) and G (7) = 7 - 3 - 1 = 3 letters (D, E, F)
- Watch for 'between' vs 'from X to Y' — they mean different things
- Reverse sequences work the same way — count backward positions
- Common trap: students count the endpoint letters too
Key formulas
Letters Between Two Points
Gap = |Position2 - Position1| - 1
When: When asked 'how many letters between X and Y'
Worked examples
Q: How many letters are there between B and F? A: B=2, F=6. Gap = 6 - 2 - 1 = 3 (C, D, E).
Q: How many letters between M and T? A: M=13, T=20. Gap = 20 - 13 - 1 = 6 (N, O, P, Q, R, S).
Coding & Pattern Recognition
SSC often codes letters using position shifts. Example: A=B, B=C (shift by +1), or A=Z, B=Y (reverse alphabet). You must identify the rule from 1-2 examples, then apply it. Common patterns: shift by fixed number, reverse alphabet, skip letters, or alternate forward-backward.
- Identify the rule from given coded example(s)
- Common rules: +1 shift, -1 shift, reverse alphabet, +2 skip, alternating
- Test rule on second example to confirm before answering
- Watch for mixed rules: some letters shift, others reverse
- Reverse alphabet coding: A↔Z, B↔Y, C↔X (use 27-position formula)
Worked examples
Q: If A=Z, B=Y, C=X, then what is D? A: Rule is reverse alphabet. D=W (27-4=23=W).
Q: If A=B, B=D, C=F, then what is E? A: Rule is position×2. E=10th letter=J.
Alphabetical Order & Ranking
Questions ask: 'Arrange these words in alphabetical order' or 'Which word comes first/last alphabetically?' Compare first letter; if same, compare second letter, and so on. This is straightforward but errors happen due to careless reading or confusion between 'comes before' and 'comes after'.
- Compare letters left-to-right, one position at a time
- If first letters differ, the word with earlier letter comes first
- If first letters same, move to second letter, and repeat
- Watch for similar words (e.g., 'cat' vs 'cats') — shorter comes first if it's a prefix
- SSC rarely tests pure alphabetical order alone; usually combined with other logic
Reverse Alphabet & Mirror Coding
A special coding where each letter maps to its mirror position: A↔Z, B↔Y, C↔X, etc. This is the most common coding in SSC CGL. The formula is simple: mirror position = 27 - original position. Alternatively, think of it as flipping the alphabet like a mirror.
- Mirror/Reverse: A=Z, B=Y, C=X, D=W, ... M=N, N=M, ... Z=A
- Formula: Mirror of Xth letter = (27-X)th letter
- Example: Mirror of E (5) = 27-5 = 22 = V
- This is symmetric: if A mirrors to Z, then Z mirrors back to A
- Useful for 'opposite letter' or 'reverse alphabet' questions
Key formulas
Mirror/Reverse Alphabet
Mirror Position = 27 - Original Position
When: When letters are coded as their reverse alphabet equivalent
Worked examples
Q: What is the mirror of letter J? A: J=10. Mirror = 27-10 = 17 = Q.
Q: In reverse alphabet, what does X represent? A: X=24. Reverse = 27-24 = 3 = C.
⚠ Common mistakes to avoid
- Confusing forward and reverse positions — always clarify: 'from left' or 'from right'?
- Counting endpoints when asked 'between' — remember gap formula excludes both endpoints
- Forgetting the -1 in gap calculation — 'between A and D' is 2 letters, not 3
- Misidentifying the coding rule — always verify with a second example before answering
- Mixing up alphabetical order with position — 'first alphabetically' ≠ 'first position in sequence'
- Arithmetic errors in reverse position: 27 - X, not 26 - X
🧠 Memory aids
- ABCDEFGHIJKLMNOPQRSTUVWXYZ — memorize in chunks: ABC, DEF, GHI, JKL, MNO, PQR, STU, VWX, YZ
- M is the middle (13th) — use as anchor for quick position recall
- Reverse = 27 - Forward — simple formula, always works
- Gap = Difference - 1 — the -1 is critical, don't forget
- Mirror alphabet: A↔Z, B↔Y, C↔X — think of a seesaw or mirror reflection
🎯 SSC CGL exam tips
- Alphabet Test questions appear in Tier 1 as 1-2 standalone questions; rarely combined with other logic in Tier 1, but common in Tier 2 as part of coding-decoding sets
- Time management: these should take 30-45 seconds max. If you're stuck, skip and return — no partial credit
- Recent SSC CGL papers show a shift toward reverse alphabet coding and gap problems; position-based questions are less frequent now
- Expect 1 question on reverse/mirror alphabet, 1 on gap/sequence, and occasionally 1 on alphabetical order in a typical Tier 1 paper
- Double-check arithmetic: position errors (off-by-one) are the #1 reason for wrong answers — verify your calculation before marking
- In Tier 2, alphabet test is often embedded in longer coding-decoding chains; master the basics here so you can apply them quickly under pressure
Q1 · medium · PYQ 2012
From the given alternatives, select the word which cannot be formed using the letters of the given word:
'CONSTITUTIONAL'
- LOCATION
- TUTION
- TALENT
- CONSULT
Q2 · medium · PYQ 2016
Arrange the following words as per order in the dictionary:
1. Zeal
2. Zebra
3. Zygote
4. Zinc
5. Zest
- 1, 2, 5, 4, 3
- 1, 2, 4, 3
- 1, 2, 5, 3, 4
- 1, 5, 2, 3, 4
Q3 · medium · PYQ 2018
Arrange the following words in a logical and meaningful order.
(1) Egypt
(2) Africa
(3) Great Pyramid
(4) World
(5) Giza
- 5, 3, 1, 4, 2
- 5, 3, 1, 2, 4
- 3, 5, 2, 1, 4
- 3, 5, 1, 2, 4
Q4 · medium · PYQ 2014
From the given alternative words, select the word which cannot be formed using the letters of the given word:
CUMBERSOME
- SOBER
- MERCY
- ROME
- MOUSE
Q5 · medium · PYQ 2018
Select the correct alternative to indicate the arrangement of the following words in a logical and meaningful order.
1. Diagnosis
2. Recovery
3. Pain
4. Treatment
5. Hospital
- 5, 3, 1, 4, 2
- 5, 1, 4, 1, 2
- 3, 5, 1, 4, 2
- 3, 5, 4, 1, 2