SSC CPO Coding-Decoding Questions with Answers: Quick Answer
This page gives 20 original SSC CPO coding-decoding questions with answers and full step-by-step explanations. Every question is written for the General Intelligence and Reasoning part of SSC CPO Paper 1: 25 questions, 25 marks, 1 mark per question, 0.25 deducted for each wrong answer, with a 15-minute sectional timer inside a 60-minute paper of 100 questions and 100 marks. The 2026 cycle has 1,871 vacancies, and the exam window is 23–28 November 2026. Coding-decoding is one of the most reliable question types in this section — the rule never changes mid-question, so a candidate who spots the rule in ten seconds banks the mark. This set covers the whole family: letter-shift codes, letter-position sum codes, number codes, substitution and word codes, symbol codes, reverse-alphabet codes, mixed letter-number codes, and one odd-one-out coding question.
Key takeaway: These 20 questions are original practice questions written for this page. They are not previous-year questions and are not copied from any paper, book or website. Every answer was checked in code: the rule was applied to the target word and to every option, and exactly one option matched the rule in each question. Work the set in about 15 minutes — 45 seconds per question, the pace the sectional timer forces — and read every explanation, including for the ones you got right.
How to Use This Set
CPO Paper 1 gives you 25 reasoning questions in 15 minutes: 36 seconds per question. Use a fixed routine. First, convert the example's letters to positions — A = 1, B = 2, up to Z = 26 — and write them under the word. Second, guess the rule: a constant shift, a sum of positions, or a reversed alphabet. Third, test the rule on every example given — a rule that fits only one example is a trap. Fourth, apply the rule to the question word, and only then look at the options; if your answer is not among them, your rule is wrong. Keep a rough sheet with the alphabet and the numbers 1 to 26 written out before the section starts.
SSC CPO Coding-Decoding Method Box
- Letter positions: A = 1, B = 2, C = 3, D = 4, E = 5, F = 6, G = 7, H = 8, I = 9, J = 10, K = 11, L = 12, M = 13, N = 14, O = 15, P = 16, Q = 17, R = 18, S = 19, T = 20, U = 21, V = 22, W = 23, X = 24, Y = 25, Z = 26. Learn the anchors: E = 5, J = 10, O = 15, T = 20, Y = 25.
- Sum codes: add the positions of all the letters. BALL is 2 + 1 + 12 + 12 = 27. Check the rule against a second example whenever one is given.
- Shift codes: each letter moves the same number of steps. A +2 shift turns LAMP into NCOR. A shift past Z wraps to A.
- Substitution codes: whole words stand for other words. Answer with the renamed word, never the real one.
- Symbol codes: each letter has its own symbol. Copy the table onto your rough sheet, then read the word letter by letter.
- Number codes: letters become their positions, written out in order or added up. B = 2, A = 1, D = 4 gives 214, not 7.
- Reverse alphabet: A and Z swap, B and Y swap. Each pair adds to 27, so subtract a letter's position from 27 to reverse it.
- Mixed codes: letters and numbers appear together. Work out what the number beside each letter means before coding the new word.
Question 1 — Letter-Shift Code
Q1. If LAMP is coded as NCOR, how is FISH coded in the same language?
(A) GJTI (B) ILVK (C) HKUJ (D) HKUK
Answer: (C) HKUJ. From LAMP → NCOR: L = 12 → N = 14, A = 1 → C = 3, M = 13 → O = 15, P = 16 → R = 18. Each letter moves two steps forward, so the rule is a +2 shift. Apply it to FISH: F = 6 + 2 = 8 = H, I = 9 + 2 = 11 = K, S = 19 + 2 = 21 = U, H = 8 + 2 = 10 = J, giving HKUJ. Option (A) is the +1 shift, (B) the +3 shift, and (D) shifts the last letter by only one.
Question 2 — Letter-Shift Code
Q2. If BIRD is coded as ZGPB, how is FISH coded in the same language?
(A) HKUJ (B) DGQF (C) EHRG (D) CFPE
Answer: (B) DGQF. From BIRD → ZGPB: B = 2 − 2 wraps to Z = 26, I = 9 − 2 = 7 = G, R = 18 − 2 = 16 = P, D = 4 − 2 = 2 = B. The rule is a −2 shift. Apply it to FISH: F = 6 − 2 = 4 = D, I = 9 − 2 = 7 = G, S = 19 − 2 = 17 = Q, H = 8 − 2 = 6 = F, giving DGQF. Option (A) is the +2 shift, (C) the −1 shift, and (D) the −3 shift.
Question 3 — Letter-Shift Code
Q3. If KING is coded as OMRK, how is LION coded in the same language?
(A) PMSR (B) OLRQ (C) QNTS (D) NKQP
Answer: (A) PMSR. From KING → OMRK: K = 11 + 4 = 15 = O, I = 9 + 4 = 13 = M, N = 14 + 4 = 18 = R, G = 7 + 4 = 11 = K. Every letter moves four steps forward, so the rule is a +4 shift. Apply it to LION: L = 12 + 4 = 16 = P, I = 9 + 4 = 13 = M, O = 15 + 4 = 19 = S, N = 14 + 4 = 18 = R, giving PMSR. Option (B) is the +3 shift, (C) the +5 shift, and (D) the +2 shift.
Question 4 — Letter-Shift Code
Q4. If FISH is coded as GKVL, how is LION coded in the same language?
(A) MJPO (B) NKQP (C) MKRS (D) MKRR
Answer: (D) MKRR. From FISH → GKVL: F + 1 = G, I + 2 = K, S + 3 = V, H + 4 = L. The shifts are 1, 2, 3, 4 — they increase by one at each letter. Apply the same increasing shift to LION: L + 1 = M, I + 2 = K, O + 3 = R, N + 4 = R, giving MKRR. Option (A) is the flat +1 shift, (B) the flat +2 shift, and (C) shifts the last letter by five instead of four.
Question 5 — Letter-Position Sum Code
Q5. If BALL is coded as 27, what is the code for CALL in the same language?
(A) 26 (B) 28 (C) 30 (D) 32
Answer: (B) 28. The code is the sum of the alphabetical positions. BALL is B = 2, A = 1, L = 12, L = 12, and 2 + 1 + 12 + 12 = 27, which matches the given code. Apply it to CALL: C = 3, A = 1, L = 12, L = 12, and 3 + 1 + 12 + 12 = 28. The words differ only in the first letter — B is 2 and C is 3 — so the code must be exactly one more than 27.
Question 6 — Letter-Position Sum Code
Q6. If MOON is coded as 57 and STAR is coded as 58, what is the code for SUN in the same language?
(A) 52 (B) 56 (C) 54 (D) 58
Answer: (C) 54. Test the sum rule on both examples. MOON is M = 13, O = 15, O = 15, N = 14, and 13 + 15 + 15 + 14 = 57. STAR is S = 19, T = 20, A = 1, R = 18, and 19 + 20 + 1 + 18 = 58. The rule fits both, so it is a plain sum code. Apply it to SUN: S = 19, U = 21, N = 14, and 19 + 21 + 14 = 54. Option (D) is the code of STAR — a trap for readers who reuse an example's answer.
Question 7 — Letter-Position Sum Code
Q7. If LIGHT is coded as 56, what is the code for NIGHT in the same language?
(A) 58 (B) 56 (C) 60 (D) 62
Answer: (A) 58. The code is the sum of the positions. LIGHT is L = 12, I = 9, G = 7, H = 8, T = 20, and 12 + 9 + 7 + 8 + 20 = 56. NIGHT shares four letters with LIGHT and differs only in the first: N = 14 against L = 12, a difference of two. So the code of NIGHT is 56 + 2 = 58. Check it directly: 14 + 9 + 7 + 8 + 20 = 58.
Question 8 — Number Code
Q8. If BAD is coded as 214, what is the code for CAB in the same language?
(A) 321 (B) 213 (C) 132 (D) 312
Answer: (D) 312. The code writes the alphabetical position of each letter, in order, with no adding. BAD is B = 2, A = 1, D = 4, written together as 214. Apply it to CAB: C = 3, A = 1, B = 2, written together as 312. Option (A) reverses the order, (B) swaps the first two digits, and (C) starts with the wrong letter.
Question 9 — Number Code
Q9. If CAT is coded as 24-26-7, what is the code for DOG in the same language?
(A) 23-12-20 (B) 23-12-21 (C) 24-12-20 (D) 23-13-20
Answer: (A) 23-12-20. This is a reverse-alphabet number code. CAT is C = 3, A = 1, T = 20 in the ordinary alphabet, but the code gives 24, 26 and 7. Each number is 27 minus the ordinary position: 27 − 3 = 24, 27 − 1 = 26, 27 − 20 = 7. Apply it to DOG: D = 4, so 27 − 4 = 23; O = 15, so 27 − 15 = 12; G = 7, so 27 − 7 = 20. That gives 23-12-20. Option (B) gets the last number wrong by one, (C) copies the first number from the CAT example, and (D) gets the middle number wrong by one.
Question 10 — Number Code
Q10. If GO is coded as 44 and ANT is coded as 105, what is the code for SUN in the same language?
(A) 54 (B) 108 (C) 162 (D) 216
Answer: (C) 162. A plain sum does not fit: GO is G = 7 + O = 15 = 22, not 44, and ANT is A = 1 + N = 14 + T = 20 = 35, not 105. But 22 × 2 = 44 and 35 × 3 = 105 — each sum is multiplied by the number of letters in the word. For SUN: S = 19, U = 21, N = 14, and the sum is 19 + 21 + 14 = 54. SUN has 3 letters, so 54 × 3 = 162. Option (A) is the sum without the multiplication, (B) multiplies by 2, and (D) multiplies by 4.
Question 11 — Substitution Code
Q11. In a certain code language, "red" is called "blue", "blue" is called "green", and "green" is called "yellow". What is the colour of grass in this code language?
(A) Red (B) Yellow (C) Blue (D) Green
Answer: (B) Yellow. Grass is green in the real world, so the question is really asking what "green" is called in this code. Follow the renaming chain to the end: "green" is called "yellow". Option (D) is the real-world answer — the trap — (A) is the start of the chain, and (C) is what "red" is called.
Question 12 — Substitution Code
Q12. In a certain code language, "mango is sweet" is written as "re mi fa", "sweet and sour" is written as "fa so ti", and "mango and lemon" is written as "re ti do". What is the code for "lemon"?
(A) re (B) ti (C) fa (D) do
Answer: (D) do. Match the words that appear in two sentences. "Mango" is in the first and third sentences, and their only common code is "re", so mango = re. "Sweet" is in the first and second, and their only common code is "fa", so sweet = fa. "And" is in the second and third, and their only common code is "ti", so and = ti. In the third sentence, "mango and lemon" is "re ti do": mango is re and and is ti, so the remaining word, lemon, must be the remaining code, do.
Question 13 — Substitution Code
Q13. In a certain code language, "bring me water" is written as "ab cd ef", "water is cold" is written as "ef gh ij", and "bring cold drink" is written as "ab ij kl". What is the code for "drink"?
(A) kl (B) ab (C) ef (D) ij
Answer: (A) kl. Match the words that appear twice. "Bring" is in the first and third sentences, and their only common code is "ab", so bring = ab. "Water" is in the first and second, and their only common code is "ef", so water = ef. "Cold" is in the second and third, and their only common code is "ij", so cold = ij. In the third sentence, "bring cold drink" is "ab ij kl": bring is ab and cold is ij, so the remaining word, drink, must be the remaining code, kl.
Question 14 — Symbol Code
Q14. In a certain code, A = @, B = #, D = %, and E = &. What is the code for BEAD?
(A) #@&% (B) &#@% (C) #&@% (D) #&%@
Answer: (C) #&@%. Read the word letter by letter and replace each one: B = #, E = &, A = @, D = %. Put them together in the same order as the letters and you get #&@%. Option (A) swaps the symbols for A and E, (B) swaps the symbols for B and E, and (D) swaps the symbols for A and D. Copy the table to your rough sheet first, then go letter by letter.
Question 15 — Symbol Code
Q15. In a certain code, ★ = S, ▲ = T, ● = O, and ■ = P. What is the code for STOP?
(A) ★●▲■ (B) ★▲●■ (C) ■▲●★ (D) ★▲■●
Answer: (B) ★▲●■. Replace each letter in order: S = ★, T = ▲, O = ●, P = ■. Put them together and STOP becomes ★▲●■. Option (A) swaps the symbols for T and O, (C) reverses the whole word, and (D) swaps the symbols for O and P.
Question 16 — Reverse-Alphabet Code
Q16. If LOVE is coded as OLEV, what is the code for HOPE in the same language?
(A) SLKW (B) RKLV (C) SMKV (D) SLKV
Answer: (D) SLKV. Test the reverse-alphabet rule on LOVE: L is 12th, 27 − 12 = 15 = O; O is 15th, 27 − 15 = 12 = L; V is 22nd, 27 − 22 = 5 = E; E is 5th, 27 − 5 = 22 = V. So LOVE becomes OLEV — each letter is replaced by the letter the same distance from the other end of the alphabet. Apply it to HOPE: H is 8th, 27 − 8 = 19 = S; O is 15th, 27 − 15 = 12 = L; P is 16th, 27 − 16 = 11 = K; E is 5th, 27 − 5 = 22 = V. That gives SLKV. Options (A), (B) and (C) each get one letter wrong.
Question 17 — Reverse-Alphabet Code
Q17. If STAR is coded as HGZI, what is the code for MOON in the same language?
(A) NLLM (B) NLLN (C) OLLM (D) NLMM
Answer: (A) NLLM. Find the rule from STAR → HGZI: S is 19th, 27 − 19 = 8 = H; T is 20th, 27 − 20 = 7 = G; A is 1st, 27 − 1 = 26 = Z; R is 18th, 27 − 18 = 9 = I. Every pair adds up to 27. Apply it to MOON: M is 13th, 27 − 13 = 14 = N; O is 15th, 27 − 15 = 12 = L; O again is L; N is 14th, 27 − 14 = 13 = M. That gives NLLM. Option (B) gets the last letter wrong, (C) the first, and (D) the third.
Question 18 — Mixed Letter-Number Code
Q18. If CAT is coded as C4 A2 T21, what is the code for DOG in the same language?
(A) D4 O15 G7 (B) D5 O15 G8 (C) D5 O16 G8 (D) D6 O16 G8
Answer: (C) D5 O16 G8. Work out what the number beside each letter means. In CAT → C4 A2 T21, C is the 3rd letter and the number beside it is 4; A is the 1st letter and the number is 2; T is the 20th letter and the number is 21. Each number is the letter's position plus one. Apply it to DOG: D is 4th, 4 + 1 = 5, so D5; O is 15th, 15 + 1 = 16, so O16; G is 7th, 7 + 1 = 8, so G8. That gives D5 O16 G8. Option (A) uses the plain positions, (B) forgets to add one to O, and (D) adds two to D.
Question 19 — Mixed Letter-Number Code
Q19. If APPLE is coded as 1PPL5, what is the code for ORANGE in the same language?
(A) 15RANG5 (B) 15R1NG5 (C) OR1NG5 (D) 15R1NGE
Answer: (B) 15R1NG5. The rule replaces each vowel with its alphabetical position and leaves consonants as letters. In APPLE → 1PPL5, A is the 1st letter, so it becomes 1; P, P and L stay as letters; E is the 5th letter, so it becomes 5. Apply it to ORANGE: O is the 15th letter, so it becomes 15; R stays R; A is the 1st letter, so it becomes 1; N and G stay as letters; E is the 5th letter, so it becomes 5. That gives 15R1NG5. Option (A) leaves the A unchanged, (C) leaves the O unchanged, and (D) leaves the E unchanged.
Question 20 — Odd-One-Out Coding
Q20. In the following, three words are coded by the same rule and one is coded by a different rule. Which one is coded differently?
(A) CAT → DBU (B) DOG → EPH (C) RAT → SBU (D) HEN → JGP
Answer: (D) HEN → JGP. Check the shift in each option. CAT → DBU is a +1 shift: C + 1 = D, A + 1 = B, T + 1 = U. DOG → EPH is a +1 shift: D + 1 = E, O + 1 = P, G + 1 = H. RAT → SBU is a +1 shift: R + 1 = S, A + 1 = B, T + 1 = U. HEN → JGP is a +2 shift: H + 2 = J, E + 2 = G, N + 2 = P — under the +1 rule HEN would be IFO, not JGP. So the first three follow the +1 rule and the fourth follows a +2 rule, making (D) the odd one out.
Common Mistakes in CPO Coding-Decoding
- Copying the example's code instead of applying the rule. In Questions 1 to 4, the code of the example word is never the answer. The example teaches the rule; the answer comes from applying it to a new word.
- Accepting a rule that fits only one example. Question 6 gives two examples for a reason: a sum code and a sum-plus-something code can agree on one word and disagree on the next.
- Forgetting the wrap in backward shifts. In Question 2, B minus 2 wraps to Z. If your subtraction goes below A, keep going from Z.
- Answering with the real word in substitution questions. In Question 11, grass really is green, but the code language calls green "yellow".
- Stopping the check after one letter. In Question 16, three wrong options get three letters right and one wrong. Check every letter.
- Mixing up sum and position codes. In Question 8, BAD becomes 214 — the positions written out — not 7, their sum.
Memory Tricks for CPO Coding-Decoding
- Anchor letters: E = 5, J = 10, O = 15, T = 20, Y = 25. Every other letter is one or two steps from an anchor.
- The 27-check for reverse alphabet. Any letter and its reverse add up to 27. To reverse a letter, subtract its position from 27.
- Differences first in sum codes. If two words share most of their letters, subtract instead of adding everything twice — Question 7 is solved in one step this way.
- Common words unlock sentence codes. In Questions 12 and 13, the word that appears in two sentences gives you its code for free.
- Copy the symbol table before you start. In Questions 14 and 15, writing the table on your rough sheet turns a memory test into a copying test.
- Say the shift out loud. "Plus two, plus two, plus two" while you code each letter stops you drifting to a different shift halfway through the word.
SSC CPO Coding-Decoding Practice Questions
Quick-fire revision — cover the answers, solve each in your head, then check.
- If SUN is coded with a +1 shift, what is the code? — TVO.
- What is the sum code of PEN? — 35 (P = 16, E = 5, N = 14).
- If BALL is coded as 27, what is the code for CALL? — 28.
- What is CAT in reverse-alphabet code? — XZG.
- What is DOG with a −1 shift? — CNF.
- What is GO with a +2 shift? — IQ.
- What is CAB in position-number code? — 312.
- If "pen" is called "pencil", "pencil" is called "book", and "book" is called "eraser", what do we write with in this code? — Pencil.
- If A = @ and B = #, what is the code for AB? — @#.
- If vowels are replaced by their positions, what is INK coded as? — 9NK (I = 9, N and K stay as letters).
SSC CPO Coding-Decoding FAQs
How many coding-decoding questions come in SSC CPO Paper 1?
There is no fixed number. Coding-decoding sits inside General Intelligence and Reasoning — 25 questions, 25 marks, 15-minute sectional timer, inside Paper 1's 100 questions and 100 marks. In recent papers it usually contributes 2 to 4 questions, so 2 to 4 marks — small, but every mark counts when 0.25 is deducted per wrong answer.
Are these CPO coding-decoding questions from previous year papers?
No. All 20 questions are original practice questions written for this page, modelled on the Paper 1 General Intelligence section's style and difficulty. Every answer was checked in code to confirm that exactly one option matches the rule. For real previous year papers, see the CPO previous year paper note linked below.
What is the fastest way to solve a coding-decoding question?
Convert the example's letters to positions first, then look for the rule: a constant shift, a sum, or a reversal. Test the rule on every example given, then apply it to the question word before looking at the options. With the anchors E = 5, J = 10, O = 15, T = 20 and Y = 25 memorised, most questions take under 30 seconds.
Does Paper 1 coding-decoding count in the final merit?
No. Paper 1 only shortlists candidates for the physical test. Final merit is based on Paper 2 marks only, plus any NCC bonus. But you cannot reach Paper 2 without clearing Paper 1, and the 15-minute sectional timer makes reasoning the section where most candidates lose time.
What should I do if my answer is not among the options?
Your rule is wrong, not the question. Re-check the rule letter by letter — the usual error is a shift that fits the first letter but not the second, or a sum code that is really a sum-times-length code like Question 10. Never force your answer onto the nearest option.
How is the 2026 CPO pattern different from the old one?
Paper 1 has halved — from 200 questions in 2 hours to 100 in 1 hour — and Paper 2 is no longer an English-only paper. This set practises the Paper 1 form: 25 reasoning questions in 15 minutes, exam window 23–28 November 2026, 1,871 vacancies in the 2026 cycle.
Which coding-decoding types should I practise most?
Letter-shift codes and letter-position sum codes first — the most frequent and the fastest to solve. Then reverse-alphabet codes and substitution codes, which cost more time per question. Symbol codes and mixed letter-number codes are rarer, but they are the easiest marks once you know the method.
Practice Next for SSC CPO Coding-Decoding
- Pattern: SSC CPO exam pattern 2026
- Syllabus: SSC CPO syllabus 2026
- Reasoning set: SSC CPO reasoning questions
- English set: SSC CPO English questions
- GK set: SSC CPO GK questions
- Coding tricks: Coding-decoding tricks for SSC CGL
- Letter series: Letter series questions for SSC
- Previous papers: SSC CPO previous year question paper
- Physical test: SSC CPO physical test 2026
- Cut-off: SSC CPO cut off
- Practice: SSC CPO Paper 1 reasoning sectional mock test 01, SSC CPO Paper 1 full mock test 01, SSC CPO reasoning mock test 01
Sources: house SSC CPO exam pattern note (Paper 1: 100 questions, 100 marks, 1 hour, 25 questions per part, 15-minute sectional timer, 0.25 negative marking; final merit on Paper 2 marks only plus NCC bonus) and house SSC CPO reasoning questions note for the question-set format. All 20 questions are original and were written for this page; every answer was verified in code by applying the rule to the target word and to every option and confirming exactly one option matched. As of 6 November 2026.