Coding Decoding— Concepts, Formulas & Shortcuts
- Letter-shift codes: compare the coded and original letters position by position; the shift is usually constant (+1, +2, −1, −3).
- Reversal codes: check whether the code is the word written backwards, or each letter replaced by its opposite (position 27 − n).
- Number codes: map each letter to a digit using the given words, then read off the answer for the new word.
- Substitution codes ("sky is blue" = "pa la ta"): find words common to two sentences to fix individual meanings.
- Mixed codes may shift vowels and consonants differently — verify with two sample letters before applying.
- Always verify your rule on the full given word before encoding the asked word.
Coding Decoding Practice Questions with Answers
Attempt each question first, then open the explanation. All 18 questions below are free to read and require no signup.
Q1.If CAT is coded as 3-1-20, then DOG is coded as:
Easy- A4-15-7
- B4-14-7
- C3-15-7
- D4-15-6
Coding Decoding question 1 of 18+Show Answer & Explanation
Answer: A. 4-15-7
Explanation: Letters are replaced by their alphabet positions: D = 4, O = 15, G = 7.
Q2.In a certain code TEACHER is written as VGCEJGT. How is CHILDREN written in that code?
Moderate- AEJKNFTGP
- BEJKNFTPG
- CEJNKFTGP
- DEKJNFTGP
Coding Decoding question 2 of 18+Show Answer & Explanation
Answer: A. EJKNFTGP
Explanation: Every letter moves two places forward. C→E, H→J, I→K, L→N, D→F, R→T, E→G, N→P gives EJKNFTGP.
Q3.If MOUSE is coded as PRXVH, how is SHIFT coded?
Moderate- AVKLIW
- BVLKIW
- CUKLIW
- DVKILW
Coding Decoding question 3 of 18+Show Answer & Explanation
Answer: A. VKLIW
Explanation: Each letter shifts three places forward: S→V, H→K, I→L, F→I, T→W.
Q4.If BOOK is written as CPPL, then PEN is written as:
Easy- AQFO
- BOFQ
- CQDM
- DODM
Coding Decoding question 4 of 18+Show Answer & Explanation
Answer: A. QFO
Explanation: Each letter moves one place forward: P→Q, E→F, N→O.
Q5.If FRIEND is coded as HTKGPF, then CANDLE is coded as:
Moderate- AECPFNG
- BEPCFNG
- CECPFGN
- DECNFPG
Coding Decoding question 5 of 18+Show Answer & Explanation
Answer: A. ECPFNG
Explanation: Each letter advances by two: C→E, A→C, N→P, D→F, L→N, E→G.
Q6.If ROSE is coded as 6821, CHAIR as 73456 and PREACH as 961473, then SEARCH is coded as:
Difficult- A214673
- B214763
- C241673
- D216473
Coding Decoding question 6 of 18+Show Answer & Explanation
Answer: A. 214673
Explanation: From the given codes: S = 2, E = 1, A = 4, R = 6, C = 7, H = 3 → SEARCH = 214673.
Q7.In a certain code LONDON is written as MPOEPO. The code follows the rule:
Easy- AEach letter moves one place forward
- BEach letter moves one place backward
- CLetters are reversed
- DVowels are doubled
Coding Decoding question 7 of 18+Show Answer & Explanation
Answer: A. Each letter moves one place forward
Explanation: L→M, O→P, N→O, D→E, O→P, N→O — a uniform +1 shift.
Q8.If DELHI is coded as 73541 and CALCUTTA as 82589662, then CALICUT is coded as:
Difficult- A8251896
- B8215896
- C8251869
- D8521896
Coding Decoding question 8 of 18+Show Answer & Explanation
Answer: A. 8251896
Explanation: From the given codes C = 8, A = 2, L = 5, I = 1, U = 9, T = 6 → CALICUT = 8-2-5-1-8-9-6.
Q9.If RED is coded as SFE, then BLUE is coded as:
Easy- ACMVF
- BCMFV
- CCNVF
- DDMVF
Coding Decoding question 9 of 18+Show Answer & Explanation
Answer: A. CMVF
Explanation: Each letter advances by one: B→C, L→M, U→V, E→F.
Q10.If CAT is coded as XZG, the code follows the rule:
Difficult- AEach letter moves forward 3
- BEach letter is replaced by its opposite letter
- CLetters are reversed
- DVowels are removed
Coding Decoding question 10 of 18+Show Answer & Explanation
Answer: B. Each letter is replaced by its opposite letter
Explanation: C↔X, A↔Z, T↔G — each letter is replaced by the one whose position sums to 27 with it.
Q11.If WATER is coded as YCVGT, then FIRE is coded as:
Moderate- AHKTG
- BHKGT
- CGKTH
- DHJTG
Coding Decoding question 11 of 18+Show Answer & Explanation
Answer: A. HKTG
Explanation: Each letter advances by two: F→H, I→K, R→T, E→G.
Q12.If 5 means 'good', 3 means 'very' and 7 means 'day', which number combination means 'very good day'?
Easy- A5 3 7
- B3 5 7
- C7 3 5
- D3 7 5
Coding Decoding question 12 of 18+Show Answer & Explanation
Answer: B. 3 5 7
Explanation: Translating word by word in order: very (3), good (5), day (7).
Q13.If MANGO is coded as 13-1-14-7-15, then PEAR is coded as:
Easy- A16-5-1-18
- B16-5-2-18
- C15-5-1-18
- D16-4-1-18
Coding Decoding question 13 of 18+Show Answer & Explanation
Answer: A. 16-5-1-18
Explanation: Each letter is replaced by its alphabet position: P = 16, E = 5, A = 1, R = 18.
Q14.If DELHI is coded as EFMIJ, the rule is:
Easy- A+1 to each letter
- B−1 from each letter
- CReverse the word
- D+2 to each letter
Coding Decoding question 14 of 18+Show Answer & Explanation
Answer: A. +1 to each letter
Explanation: D→E, E→F, L→M, H→I, I→J — a uniform forward shift of one.
Q15.In a code, PAPER is written as REPAP. How is BOOK written?
Easy- AKOOB
- BOKOB
- CBKOO
- DOOKB
Coding Decoding question 15 of 18+Show Answer & Explanation
Answer: A. KOOB
Explanation: The code simply reverses the letters, so BOOK becomes KOOB.
Q16.If GARDEN is coded as ICTFGP, then FLOWER is coded as:
Moderate- AHNQYGT
- BHNQGYT
- CGNQYGT
- DHMQYGT
Coding Decoding question 16 of 18+Show Answer & Explanation
Answer: A. HNQYGT
Explanation: Each letter advances by two: F→H, L→N, O→Q, W→Y, E→G, R→T.
Q17.If in a code 'sky' is 'blue', 'blue' is 'cloud' and 'cloud' is 'rain', what covers the earth's atmosphere?
Difficult- Asky
- Bblue
- Ccloud
- Drain
Coding Decoding question 17 of 18+Show Answer & Explanation
Answer: B. blue
Explanation: The sky covers the atmosphere, and in this code 'sky' is called 'blue'.
Q18.If A = 26, B = 25, C = 24, then what is the value of H?
Moderate- A17
- B18
- C19
- D20
Coding Decoding question 18 of 18+Show Answer & Explanation
Answer: C. 19
Explanation: The code is 27 − alphabet position. H is 8th, so 27 − 8 = 19.
Coding Decoding — Frequently Asked Questions
What is the fastest way to crack a letter-shift code?+
Line up the first letters of the original and the code and count the gap, then confirm with the last letters. If both give the same shift, apply it mechanically to the target word.
How do substitution-code sentence questions work?+
Find a word that appears in two of the given sentences; the code word common to both sentences must correspond to it. Repeat until every word is pinned down.
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