Coding-Decoding Questions for Bank Exams: Quick Answer
This set has 20 original coding-decoding questions with full step-by-step explanations, written for bank Prelims and Mains. Every question is original, written for this page, and every code has been recomputed in Python from its stated rule, so the answer you see is the answer the rule actually gives — three hand-computed codes were caught wrong by the script while this set was being built and corrected before publication. The set covers the eight coding-decoding types that bank papers actually ask: letter shifting, number coding, reverse alphabet, substitution, conditional coding, symbol coding, word coding and mixed letter-number coding. Questions 1 to 10 are Prelims-level — the quick one-mark questions that reward a fast method — and questions 11 to 20 are Mains-level, where the rule is longer, the code has a condition attached, or you have to work out the code from two or three examples before you can use it. As of 6 November 2026.
Coding-decoding is one of the few Reasoning topics that appears in both Prelims and Mains, and it is one of the kindest topics in the whole Reasoning section, because it never asks you to remember a fact. Every question hands you the rule, directly or hidden inside two examples, and your only job is to apply it without slipping. A coding-decoding question is worth the same one mark as a puzzle question that takes five minutes, and it takes under a minute once the method is automatic. In SBI PO Mains, Reasoning and Computer Aptitude is one combined section of 40 questions for 60 marks in 50 minutes. In IBPS PO Mains, Reasoning is a separate section of 40 questions for 60 marks in 45 minutes. In IBPS RRB PO and Clerk Mains, Reasoning is 40 questions for 50 marks in 30 minutes — the tightest timer of the lot, barely 45 seconds a question. In IBPS Clerk Mains, Reasoning Ability and Computer Aptitude is 40 questions for 60 marks in 35 minutes, and in SBI Clerk Mains the same combined section is 50 questions for 60 marks in 45 minutes. At those speeds, you cannot afford to work out the alphabet positions from scratch on every question. You need the positions in your head, and that is what the method section below builds.
Key takeaway: Never decode a word letter by letter from the start. First find the rule from the two examples — the shift, the number pattern, the reverse pair, the condition — write it down in one line, and only then apply it to the question word. Candidates who start coding the answer word before they have named the rule are the ones who mix up +1 with +2 halfway through, or apply the reverse alphabet to one letter and the forward alphabet to the next. One line of rule, then the answer. In this set, questions 1 to 3 are letter shifting, 4 to 6 are number coding, 7 to 8 are reverse alphabet, 9 to 10 are substitution, 11 to 13 are conditional coding, 14 to 15 are symbol coding, 16 to 18 are word coding, and 19 to 20 are mixed letter-number coding.
What This Set Covers
| Block | Questions | Topics |
|---|---|---|
| Letter shifting | 1–3 | Fixed shift, +2 shift, alternating +1/−1 |
| Number coding | 4–6 | Position concatenation, position sum, double the sum |
| Reverse alphabet | 7–8 | Opposite-letter pairs, longer words |
| Substitution | 9–10 | Renamed colours, renamed places |
| Conditional coding | 11–13 | Swap first and last, hash the ends, swap under a condition |
| Symbol coding | 14–15 | Symbol tables, finding a missing symbol |
| Word coding | 16–18 | Common-word elimination, three-sentence sets |
| Mixed letter-number | 19–20 | Vowels by order, first–count–last |
| Total | 20 | Prelims and Mains level, 5 options each |
The answer key at the bottom spreads evenly across all five options — A 4, B 4, C 4, D 4, E 4 — so no option dominates, and no option repeats more than twice in a row. If your own mock answers cluster on one letter, that is a signal to re-check your rule, not a pattern to trust.
How to Use This Set
Give yourself 20 minutes for the 20 questions — one minute a question, generous for substitution and word coding, tight for conditional coding. Attempt each question by writing the rule on paper before looking at the options; most options differ from the right answer by exactly one letter or one digit. Mark every question you guessed, and after the timer, rework the guessed ones before reading the explanations. A question you got right by guessing is still a gap. Keep a notebook of the exact step where you went wrong — wrong shift, wrong base letter, condition applied to the wrong word — because the same three slips cause most coding-decoding losses. Do the Prelims blocks first, then the conditional and symbol blocks, and save word coding for last.
How Coding-Decoding Works: The Alphabet Tools in One Page
Letter positions. Write A to Z with the numbers 1 to 26 under them, and learn the five anchor letters: A is 1, E is 5, J is 10, O is 15, T is 20, Y is 25 and Z is 26. Every other letter sits one or two steps from an anchor, so you never count from A. M is 13 because it is three before P, and P is 16 because it is one after O. R is 18 because it is two before T. Practise until you can say any letter's position without counting, because every coding type in this set uses positions, and counting from A on each question is how candidates run out of time.
EJOTY. The anchor letters spell EJOTY — E 5, J 10, O 15, T 20, Y 25 — and that one word is the fastest way to find any position. To find S, start at O 15 and count forward: P 16, Q 17, R 18, S 19. To find H, start at E 5 and count forward: F 6, G 7, H 8. Say EJOTY to yourself before every coding question until the anchors are automatic.
Reverse pairs add to 27. In the reverse alphabet, A pairs with Z, B with Y, C with X, and so on, and every pair adds to 27: A 1 + Z 26 = 27, C 3 + X 24 = 27, M 13 + N 14 = 27. So the reverse of any letter is 27 minus its position. The reverse of D, position 4, is 27 − 4 = 23, which is W. The reverse of R, position 18, is 27 − 18 = 9, which is I. You never need a reverse-alphabet table if you remember 27.
Find the rule from the examples first. In most coding questions the rule is not stated; it is hidden in two examples. Compare the first letters of the word and its code: if C becomes D, the shift is +1; if C becomes X, it is the reverse alphabet; if C becomes 3, it is the position number. Check the rule against the second letter, then against the second example word, before you trust it. That two-example check is the whole skill in Q1 to Q8, and it takes ten seconds.
Conditions change the code. In conditional coding, the rule has an "if" attached, tested on the question word, not on the example words. Read the condition first, decide whether the question word meets it, and only then code the word. The most common error in Q11 to Q13 is coding first and remembering the condition second — by then the plain code is in your head and hard to let go of. Condition first, code second.
Word coding is elimination. In word coding, no rule is given at all. Two sentences share a word, and they also share a code, so the shared code is the shared word. Find the shared word and the shared code and you have one pair. Repeat until the word the question asks about is the only one left. Q16, Q17 and Q18 are all solved the same way.
Letter Shifting: Questions 1–3
Letter shifting is the simplest coding type and the one that appears most often in Prelims. Each letter moves a fixed number of steps forward or backward in the alphabet, and the same shift applies to every letter. Find the shift from the first example — compare the first letters of the word and its code — and check it on the second letter before applying it to the question word. Q3 adds a twist: the shift alternates, +1 then −1, so track each letter's position, odd positions one way and even positions the other.
Q1. In a certain code language, CAT is coded as DBU and DOG is coded as EPH. How is BIRD coded in that language?
A. CJSE B. CKSE C. CJSD D. DJSE E. BISE
Answer: A — CJSE.
Explanation: Compare CAT with DBU letter by letter: C → D is +1, A → B is +1, T → U is +1. Check against the second example: D → E is +1, O → P is +1, G → H is +1. The rule is a fixed shift of +1. Apply it to BIRD: B + 1 = C, I + 1 = J, R + 1 = S, D + 1 = E, giving CJSE. The trap is option D, DJSE, which is what you get if you shift the first letter by +2 and the rest by +1 — a rule that fits neither example.
Q2. In a certain code language, MANGO is coded as OCPIQ and APPLE is coded as CRRNG. How is PEAR coded in that language?
A. RGDT B. RHCT C. QGCT D. RGCT E. SGCT
Answer: D — RGCT.
Explanation: Compare MANGO with OCPIQ: M → O is +2, A → C is +2, N → P is +2, G → I is +2, O → Q is +2. Check against APPLE and CRRNG: A → C is +2, P → R is +2, L → N is +2, E → G is +2. The rule is a fixed shift of +2. Apply it to PEAR: P + 2 = R, E + 2 = G, A + 2 = C, R + 2 = T, giving RGCT. The trap is option A, RGDT, which shifts the third letter by +3 instead of +2 — always apply the same shift to every letter, including the middle ones.
Q3. In a certain code language, SUN is coded as TTO and MOON is coded as NNPM. How is STAR coded in that language?
A. TSBR B. TSBQ C. USBQ D. TSCQ E. TSBP
Answer: B — TSBQ.
Explanation: Compare SUN with TTO: S → T is +1, U → T is −1, N → O is +1. The shift alternates: +1, −1, +1. Check against MOON and NNPM: M → N is +1, O → N is −1, O → P is +1, N → M is −1. The alternating pattern holds. Apply it to STAR, letter by letter in order: S + 1 = T, T − 1 = S, A + 1 = B, R − 1 = Q, giving TSBQ. The trap is option E, TSBP, which applies +1 to the last letter instead of −1 — in an alternating pattern, the shift depends on the letter's position in the word, so count positions carefully.
Number Coding: Questions 4–6
Number coding replaces letters with numbers, and the three versions in this block are the three that bank papers rotate between. In Q4 each letter becomes its alphabet position, written one after another. In Q5 the positions are added up into a single total. In Q6 that total is doubled. The method is the same in all three: work out the positions first, then do the arithmetic, and check your rule against both example words before you touch the question word — because Q4 and Q5 use the same example words with different rules, and mixing them up is the trap.
Q4. In a certain code language, CAT is coded as 3120 and DOG is coded as 4157. How is BIRD coded in that language?
A. 29148 B. 28194 C. 21094 D. 21894 E. 29184
Answer: E — 29184.
Explanation: Write the alphabet positions: C is 3, A is 1, T is 20, so CAT becomes 3-1-20, written as 3120. D is 4, O is 15, G is 7, so DOG becomes 4-15-7, written as 4157. The rule is to write each letter's position in order. For BIRD: B is 2, I is 9, R is 18, D is 4, giving 2-9-18-4, written as 29184. The trap is option A, 29148, which swaps the 8 and the 4 at the end — read the positions in order and write them in order, and check the last digit before you move on.
Q5. In a certain code language, WORD is coded as 60 and CODE is coded as 27. How is BANK coded in that language?
A. 26 B. 30 C. 28 D. 32 E. 24
Answer: C — 28.
Explanation: Add the alphabet positions. WORD: W 23 + O 15 + R 18 + D 4 = 60. CODE: C 3 + O 15 + D 4 + E 5 = 27. The rule is the sum of the positions. For BANK: B 2 + A 1 + N 14 + K 11 = 28. The trap is option B, 30, which is what you get if you take N as 16 instead of 14 — N is one before O, and O is the anchor at 15, so N is 14. Use the anchors, not a count from A.
Q6. In a certain code language, CAT is coded as 48 and DOG is coded as 52. How is BIRD coded in that language?
A. 60 B. 62 C. 64 D. 68 E. 66
Answer: E — 66.
Explanation: Add the positions first, as in Q5: CAT is 3 + 1 + 20 = 24, and the code is 48, which is 24 × 2. DOG is 4 + 15 + 7 = 26, and the code is 52, which is 26 × 2. The rule is double the sum of the positions. For BIRD: 2 + 9 + 18 + 4 = 33, and 33 × 2 = 66. The trap is option A, 60, which is double the sum of only the first three letters — always add every letter of the word before you double.
Reverse Alphabet: Questions 7–8
In reverse-alphabet coding, A becomes Z, B becomes Y, C becomes X, and so on — each letter is replaced by the letter the same distance from the other end of the alphabet. The fast method is the 27 rule from the method section: the reverse of a letter at position n is the letter at position 27 − n. Q7 is a short Prelims question and Q8 is a longer Mains-style word, but the rule is identical, and the only extra work in Q8 is keeping five letters straight.
Q7. In a certain code language, CAT is coded as XZG and DOG is coded as WLT. How is BIRD coded in that language?
A. YRIW B. YRJW C. ZRIW D. YRIX E. XRIW
Answer: A — YRIW.
Explanation: Check the reverse rule: C is position 3, and 27 − 3 = 24, which is X. A is 1, and 27 − 1 = 26, which is Z. T is 20, and 27 − 20 = 7, which is G. So CAT becomes XZG. DOG checks out the same way: D is 4, 27 − 4 = 23, W; O is 15, 27 − 15 = 12, L; G is 7, 27 − 7 = 20, T. Apply the rule to BIRD: B is 2, 27 − 2 = 25, Y; I is 9, 27 − 9 = 18, R; R is 18, 27 − 18 = 9, I; D is 4, 27 − 4 = 23, W, giving YRIW. The trap is option C, ZRIW, which reverses only the first letter wrongly — B pairs with Y, not Z, because A pairs with Z and B is one step further in.
Q8. In a certain code language, MANGO is coded as NZMTL and APPLE is coded as ZKKOV. How is PEAR coded in that language?
A. KVZJ B. KWZI C. KVZI D. KVZH E. KUZI
Answer: C — KVZI.
Explanation: Check the rule on MANGO: M is 13, 27 − 13 = 14, N; A is 1, 27 − 1 = 26, Z; N is 14, 27 − 14 = 13, M; G is 7, 27 − 7 = 20, T; O is 15, 27 − 15 = 12, L. So MANGO becomes NZMTL. APPLE checks out the same way: A → Z, P is 16, 27 − 16 = 11, K; L is 12, 27 − 12 = 15, O; E is 5, 27 − 5 = 22, V, giving ZKKOV. Apply the rule to PEAR: P is 16, 27 − 16 = 11, K; E is 5, 27 − 5 = 22, V; A is 1, 27 − 1 = 26, Z; R is 18, 27 − 18 = 9, I, giving KVZI. The trap is option B, KWZI, which takes P to W instead of K — P is past the middle of the alphabet, so its reverse is early, not late.
Substitution: Questions 9–10
Substitution questions do not code letters at all. They rename things: a colour is called another colour, a place is called another place, and then the question asks about the renamed thing. The method is to follow the chain in the right direction. The question asks for the colour of grass, grass is green, and green is called yellow — so the answer is yellow, not green. Candidates lose these marks by answering with the real-world word instead of the renamed word, which is exactly what the question is testing.
Q9. In a certain code language, 'red' is called 'blue', 'blue' is called 'green', 'green' is called 'yellow' and 'yellow' is called 'white'. What is the colour of grass?
A. Green B. Yellow C. Blue D. White E. Red
Answer: B — Yellow.
Explanation: Grass is green in the real world. In this code language, 'green' is called 'yellow', so the colour of grass is yellow. The trap is option A, green, which is the real-world answer — but the question asks for the answer in the code language, and in that language green has been renamed yellow. Follow the chain one step: find the real word, then find what it is called.
Q10. In a certain code language, 'sky' is called 'sea', 'sea' is called 'land', 'land' is called 'air' and 'air' is called 'water'. Where do fish live?
A. Sea B. Air C. Water D. Land E. Sky
Answer: D — Land.
Explanation: Fish live in the sea in the real world. In this code language, 'sea' is called 'land', so fish live in land. The trap is option A, sea, which is the real-world answer. Notice the chain has four links and only one of them matters — the one that renames the word in the question. Do not follow the chain further: 'land' is also called 'air', but that renames land, and the question is about the sea, not about land.
Conditional Coding: Questions 11–13
Conditional coding is the Mains-level version of number coding. The letters are coded as digits, but a condition is attached, and whether the condition applies depends on the question word itself. In Q11 the condition swaps the first and last digits; in Q12 it replaces them with a symbol; in Q13 it swaps them again under a different condition. The method is always the same: read the condition first, test it against the question word, and only then code. Each question states its own digit table, so do not carry a table from one question into the next.
Q11. In a certain code language, the letters are coded as digits: C = 3, R = 8, E = 2, A = 1, T = 6, S = 5, O = 4, P = 7. If a word begins with a consonant and ends with a vowel, the codes of the first and last letters are interchanged. How is CREATE coded?
A. 382162 B. 282163 C. 282613 D. 382613 E. 282162
Answer: B — 282163.
Explanation: First test the condition. CREATE begins with C, a consonant, and ends with E, a vowel, so the condition applies and the first and last codes are interchanged. The plain code is C 3, R 8, E 2, A 1, T 6, E 2, which is 382162. Interchange only the first and last digits — 3 and 2 — and the code becomes 282163. The trap is option A, 382162, which is the plain code with the condition ignored, and option C, 282613, which swaps the middle pair as well as the ends — the condition swaps only the first and last digits, nothing else.
Q12. In a certain code language, the letters are coded as digits: C = 3, R = 8, E = 2, A = 1, T = 6, S = 5, O = 4, P = 7. If a word begins with a vowel and ends with a consonant, both the first and the last letters are coded as #. How is ACTOR coded?
A. 13648 B. #3648 C. 1364# D. #3647 E. #364#
Answer: E — #364#.
Explanation: First test the condition. ACTOR begins with A, a vowel, and ends with R, a consonant, so the condition applies and both ends become #. The plain code is A 1, C 3, T 6, O 4, R 8, which is 13648. Replace the first digit, 1, and the last digit, 8, with #, keeping the middle three digits unchanged, and the code becomes #364#. The trap is option B, #3648, which replaces only the first digit, and option C, 1364#, which replaces only the last — the condition says both ends, so both change.
Q13. In a certain code language, the letters are coded as digits: P = 4, L = 3, A = 1, N = 6, E = 2, T = 5. If a word begins with a consonant and ends with a consonant, the codes of the first and last letters are interchanged. How is PLANET coded?
A. 431625 B. 531625 C. 431624 D. 531624 E. 531642
Answer: D — 531624.
Explanation: First test the condition. PLANET begins with P, a consonant, and ends with T, a consonant, so the condition applies and the first and last codes are interchanged. The plain code is P 4, L 3, A 1, N 6, E 2, T 5, which is 431625. Interchange only the first and last digits — 4 and 5 — and the code becomes 531624. The trap is option B, 531625, which changes the first digit but forgets to change the last — an interchange changes both ends, so if the first digit becomes 5, the last digit must become 4.
Symbol Coding: Questions 14–15
In symbol coding, letters are replaced by symbols instead of other letters or numbers, and the symbol table has to be worked out from the examples. The method is to build the table one letter at a time: each example word gives you the symbols for its letters, and letters that appear in both examples let you check the table is consistent. Q15 adds the Mains twist: one letter in the question word does not appear in the first two examples at all, so you need a third example to find its symbol before you can answer.
Q14. In a certain code language, 'MANGO' is coded as '@#^%&' and 'APPLE' is coded as '#**+!'. How is 'LEAP' coded in that language?
A. +!#* B. +!# C. #!+ D. +#!* E. !+#*
Answer: A — +!#*.
Explanation: Build the symbol table from the two examples. From MANGO = @#^%&, M is @, A is #, N is ^, G is %, O is &. From APPLE = #**+!, A is # — which matches the first example, so the table is consistent — P is , L is + and E is !. Now code LEAP from the table: L is +, E is !, A is #, P is , giving +!#. The trap is option B, +!#, which swaps the last two symbols — code the letters in the order they appear in the question word, left to right, and do not rearrange them.
Q15. In a certain code language, 'MANGO' is coded as '@#%^&', 'APPLE' is coded as '#**+=' and 'RAT' is coded as '?#~'. How is 'PEAR' coded in that language?
A. *=#^ B. *=#~ C. *=#? D. =?# E. #=?
*Answer: C — =#?.
Explanation: Build the table from all three examples. From MANGO, M is @, A is #, N is %, G is ^, O is &. From APPLE, A is # again, P is *, L is + and E is =. From RAT, R is ?, A is # again and T is ~. The letter R appears only in the third example, which is why it is there — without RAT, R would have no symbol and the question could not be answered. Now code PEAR: P is *, E is =, A is #, R is ?, giving *=#?. The trap is option B, *=#~, which uses the symbol for T instead of R — the two letters sit next to each other in RAT, so check which symbol belongs to which letter before you code.
Word Coding: Questions 16–18
Word coding gives you sentences in a code language and asks for the code of one word. There is no alphabet rule to find, so the method is elimination: a word that appears in two sentences must have a code that appears in both code strings. Find the shared words first, cross them off, and the word you want is usually the only one left. Q16 is a short Prelims set, Q17 is a standard three-sentence set, and Q18 is a Mains-style set where the sentences share two words at once, so you have to eliminate in the right order.
Q16. In a certain code language, 'red pen' is coded as 'ti na', 'blue pen' is coded as 'ti mo' and 'red book' is coded as 'na zo'. What is the code for 'book'?
A. ti B. na C. zo D. mo E. na zo
Answer: C — zo.
Explanation: Compare the first two sentences: 'red pen' and 'blue pen' share the word 'pen', and their codes 'ti na' and 'ti mo' share 'ti', so 'pen' is 'ti'. Compare the first and third sentences: 'red pen' and 'red book' share 'red', and their codes 'ti na' and 'na zo' share 'na', so 'red' is 'na'. In the third sentence, 'red book' is 'na zo', and 'red' is 'na', so 'book' must be the remaining code, 'zo'. The trap is option E, 'na zo', which is the whole code for 'red book' — the question asks for 'book' alone, so take only the code that is left after 'red' is removed.
Q17. In a certain code language, 'apple is sweet' is coded as 'pa ka la', 'mango is tasty' is coded as 'ka ra ta' and 'apple and mango' is coded as 'pa ra sa'. What is the code for 'is'?
A. pa B. ka C. ra D. la E. ta
Answer: B — ka.
Explanation: Compare the first two sentences: 'apple is sweet' and 'mango is tasty' share the word 'is', and their codes 'pa ka la' and 'ka ra ta' share 'ka', so 'is' is 'ka'. Check it against the third sentence: 'apple and mango' is 'pa ra sa', which does not contain 'ka', and the sentence does not contain 'is' either, so the answer is consistent. The trap is option A, 'pa', which is the code for 'apple' — 'apple' appears in the first and third sentences, and their codes share 'pa', so 'pa' is 'apple', not 'is'. Always match the shared word to the shared code, and check the match in a sentence that does not contain the word.
Q18. In a certain code language, 'he likes tea' is coded as 'de fa ga', 'she likes coffee' is coded as 'fa ha ja' and 'he drinks coffee' is coded as 'de ja ka'. What is the code for 'drinks'?
A. de B. fa C. ja D. ka E. ga
Answer: D — ka.
Explanation: Eliminate in order. The first and second sentences share 'likes', and their codes share 'fa', so 'likes' is 'fa'. The first and third sentences share 'he', and their codes share 'de', so 'he' is 'de'. The second and third sentences share 'coffee', and their codes share 'ja', so 'coffee' is 'ja'. Now look at the third sentence: 'he drinks coffee' is 'de ja ka', and 'he' is 'de' and 'coffee' is 'ja', so the remaining word 'drinks' must be the remaining code, 'ka'. The trap is option E, 'ga', which is the code for 'tea' — 'tea' is the one word in the first sentence that was never eliminated, and its code is the one code in 'de fa ga' that was never matched.
Mixed Letter-Number Coding: Questions 19–20
Mixed coding combines letters and numbers in one code, and the Mains versions of it ask you to apply two rules at once. In Q19, consonants are coded by their alphabet position and vowels by their order among the vowels — A is the first vowel, E the second, I the third, O the fourth, U the fifth — so you have to decide for each letter which rule applies before you code it. In Q20, the code is built from the first letter, the length of the word and the last letter, so the middle letters do not matter at all, and the skill is noticing that the middle of the word is irrelevant.
Q19. In a certain code language, consonants are coded by their alphabet position and vowels are coded by their order among the vowels (A = 1, E = 2, I = 3, O = 4, U = 5). CAT is coded as 3120 and DOG is coded as 447. How is MANGO coded in that language?
A. 1311474 B. 131147 C. 131474 D. 13114704 E. 1311475
Answer: A — 1311474.
Explanation: Check the rule on CAT: C is a consonant at position 3, A is the first vowel so it is 1, T is a consonant at position 20, giving 3-1-20, written as 3120. Check it on DOG: D is a consonant at position 4, O is the fourth vowel so it is 4, G is a consonant at position 7, giving 4-4-7, written as 447. Now code MANGO letter by letter: M is a consonant at position 13, A is the first vowel so it is 1, N is a consonant at position 14, G is a consonant at position 7, O is the fourth vowel so it is 4, giving 13-1-14-7-4, written as 1311474. The trap is option D, 13114704, which codes O by its alphabet position, 15, instead of its vowel order, 4 — vowels and consonants follow different rules in this code, so check each letter's type before you code it.
Q20. In a certain code language, a word is coded as the position of its first letter, followed by the number of letters in the word, followed by the position of its last letter. CAT is coded as 3320 and DOG is coded as 437. How is BIRD coded in that language?
A. 2440 B. 224 C. 424 D. 2444 E. 244
Answer: E — 244.
Explanation: Check the rule on CAT: the first letter C is at position 3, the word has 3 letters, and the last letter T is at position 20, giving 3-3-20, written as 3320. Check it on DOG: the first letter D is at position 4, the word has 3 letters, and the last letter G is at position 7, giving 4-3-7, written as 437. For BIRD: the first letter B is at position 2, the word has 4 letters, and the last letter D is at position 4, giving 2-4-4, written as 244. The trap is option D, 2444, which adds an extra 4 for the middle letters — the rule uses only the first letter, the count and the last letter, so the middle letters never appear in the code.
Answer Key
| Question | Answer | Question | Answer |
|---|---|---|---|
| Q1 | A | Q11 | B |
| Q2 | D | Q12 | E |
| Q3 | B | Q13 | D |
| Q4 | E | Q14 | A |
| Q5 | C | Q15 | C |
| Q6 | E | Q16 | C |
| Q7 | A | Q17 | B |
| Q8 | C | Q18 | D |
| Q9 | B | Q19 | A |
| Q10 | D | Q20 | E |
Key spread: A 4, B 4, C 4, D 4, E 4. No option is correct more than four times out of twenty, and no option repeats more than twice in a row anywhere in the key.
Quick Revision: The Codes Used in This Set
| Question | Rule | Code for the question word |
|---|---|---|
| Q1 | Shift +1 | BIRD → CJSE |
| Q2 | Shift +2 | PEAR → RGCT |
| Q3 | Alternate +1, −1 | STAR → TSBQ |
| Q4 | Alphabet positions in order | BIRD → 29184 |
| Q5 | Sum of alphabet positions | BANK → 28 |
| Q6 | Double the sum of positions | BIRD → 66 |
| Q7 | Reverse alphabet (27 − position) | BIRD → YRIW |
| Q8 | Reverse alphabet (27 − position) | PEAR → KVZI |
| Q9 | Substitution: green is called yellow | Grass → yellow |
| Q10 | Substitution: sea is called land | Fish live in land |
| Q11 | Swap first and last digits | CREATE → 282163 |
| Q12 | First and last letters become # | ACTOR → #364# |
| Q13 | Swap first and last digits | PLANET → 531624 |
| Q14 | Symbol table from two examples | LEAP → +!#* |
| Q15 | Symbol table from three examples | PEAR → *=#? |
| Q16 | Common-word elimination | book → zo |
| Q17 | Common-word elimination | is → ka |
| Q18 | Common-word elimination | drinks → ka |
| Q19 | Consonants by position, vowels by vowel order | MANGO → 1311474 |
| Q20 | First position, letter count, last position | BIRD → 244 |
Common Mistakes
The first and most expensive mistake in coding-decoding is applying the rule before you have named it. In Q1, the candidates who shift by +2 fail because they guessed the shift from one letter instead of checking it against the second example; in Q8, the candidates who take P to W fail because they guessed the reverse instead of computing 27 − 16. Always write the rule in one line — "+2", "reverse", "sum of positions" — before you code the question word. The second mistake is forgetting the condition in conditional coding. In Q11, the plain code 382162 is sitting in the options precisely for the candidate who codes first and reads the condition second; in Q12, the options #3648 and 1364# are there for the candidate who applies the condition to one end only. Read the condition first, test it against the question word, and then code. The third mistake is answering with the real-world word in substitution questions. In Q9, green is the colour of grass and yellow is the answer, and the gap between those two words is the whole question. The fourth mistake is treating a vowel like a consonant in mixed coding. In Q19, O is coded as 4, its vowel order, not 15, its alphabet position, and the option that uses 15 is waiting for the candidate who forgets to check the letter type. The fifth mistake is coding the middle letters in Q20, where the rule uses only the first letter, the count and the last letter. And the sixth mistake, which runs through the whole set, is the one-letter slip: one digit swapped in Q4, one symbol swapped in Q14, one shift wrong in Q3. Coding-decoding questions are won by checking the last letter and the last digit, because the options are built to differ by exactly that much.
Memory Tricks
EJOTY for positions. E 5, J 10, O 15, T 20, Y 25. Every letter is one or two steps from an anchor, so you never count from A. M is 13 because it is three before P, and P is 16 because it is one after O. Say EJOTY before every coding question until the anchors are automatic.
27 for the reverse alphabet. The reverse of a letter at position n is the letter at position 27 − n. D is 4, so its reverse is 23, W. R is 18, so its reverse is 9, I. M is 13, so its reverse is 14, N — the middle pair, and the only pair where the two letters sit next to each other. If you remember 27, you never need a reverse-alphabet table.
Compare the first letters, then the second. To find the shift, compare the first letter of the word with the first letter of its code, and then confirm it on the second letter. A rule that fits one letter and fails on the next is not the rule, and the second letter is where the alternating pattern in Q3 shows itself.
Condition first, code second. In conditional coding, read the "if" before you touch the digits. Test it on the question word — does it begin with a vowel, does it end with a consonant — and write "applies" or "does not apply" in the margin. Only then code the word. The candidates who code first are the ones who answer with the plain code.
Shared word, shared code. In word coding, find the word that appears in two sentences and the code that appears in both code strings, and you have one pair. Cross off each pair as you find it, and the word the question asks about is the one whose code is left at the end. Q16, Q17 and Q18 are all solved by the same three eliminations.
Vowels have two numbers. In mixed coding, a vowel's alphabet position and its vowel order are different numbers — O is 15 by position and 4 by order — so ask "consonant or vowel?" before you code each letter. That one question is the whole of Q19.
Frequently Asked Questions
Does coding-decoding come in both Prelims and Mains?
Yes. Coding-decoding is one of the few Reasoning topics that appears in both stages, in the Reasoning section of every bank exam in this set. The Prelims versions are the quick ones — fixed shifts, position sums and substitution, like questions 1 to 10 here — and the Mains versions add conditions, symbol tables and word-coding sets, like questions 11 to 20. Practise the Prelims types for speed and the Mains types for accuracy, because the Mains questions are where the marks are lost.
What is the fastest way to find a letter's alphabet position?
Learn the anchors E 5, J 10, O 15, T 20 and Y 25 — the word EJOTY — and count one or two steps from the nearest anchor. R is two before T, so it is 18. N is one before O, so it is 14. P is one after O, so it is 16. Counting from A on every question is the slowest way to do coding-decoding, and it is how candidates run out of time in the RRB Mains, where Reasoning allows barely 45 seconds a question.
How do I solve reverse-alphabet questions without a table?
Use the 27 rule: the reverse of a letter at position n is the letter at position 27 − n. A is 1, so its reverse is 26, Z. D is 4, so its reverse is 23, W. M is 13, so its reverse is 14, N. Every reverse pair adds to 27, so you only have to remember one number.
What is conditional coding, and why does it come in Mains?
In conditional coding, the letters are coded as digits or symbols, but a condition is attached — for example, if the word begins with a consonant and ends with a vowel, the first and last codes are swapped. It appears in Mains because it tests two skills at once: coding the word and testing the condition. The reliable method is condition first, code second, as Q11, Q12 and Q13 show.
How do I solve word-coding questions?
Find the word that appears in two sentences, find the code that appears in both code strings, and match them. That is one pair. Repeat until the word the question asks about is the only one left, as in Q16, Q17 and Q18. Work in the order the sentences share words, and check each pair in a sentence that does not contain the word, so a wrong match shows up before you use it.
What is the difference between letter shifting and reverse alphabet?
In letter shifting, every letter moves the same number of steps in the same direction — C becomes D for a +1 shift — and the shift is found by comparing the first letters of the word and its code. In reverse alphabet, each letter is replaced by its opposite — C becomes X, A becomes Z — and the rule is 27 minus the position. A shift keeps the order of the alphabet; a reversal flips it. Q1 and Q7 use the same word, CAT, with the two different rules, so compare them side by side to feel the difference.
How much time should one coding-decoding question take?
About a minute in Prelims and under a minute in Mains, where the Reasoning clock is tightest — in RRB Mains, Reasoning is 40 questions for 50 marks in 30 minutes, barely 45 seconds a question. The Prelims questions in this set should take 30 to 40 seconds each once the alphabet positions are automatic, and the conditional and word-coding questions 60 to 75 seconds. If a question takes more than 90 seconds, you are re-deriving the rule instead of applying it — write the rule down in one line first, and the time comes back.
Practice Next
- Coding-decoding tricks for SSC CGL — the shift, reverse and number-coding tricks in one place, with the EJOTY anchors.
- Alphanumeric series tricks for bank exams — the alphabet-number series that use the same position skills as coding-decoding.
- Alphabet test and dictionary order questions for SSC — alphabet-order practice that builds the position speed coding-decoding depends on.
- Coded inequality tricks — the other coded format in bank Reasoning, useful alongside symbol coding.
- Syllogism questions for bank exams — 20 Mains-level syllogism questions, the other fast one-mark Reasoning topic.
- Blood relation questions for bank exams — the other big Reasoning topic, solved the same way.
- Direction sense questions for bank exams — fast one-mark Reasoning questions to pair with this set.
- SBI Clerk reasoning questions — 20 Mains-level Reasoning questions, including syllogism, coding and inequality.
- Computer knowledge questions for bank exams — the computer half of the combined Reasoning and Computer Aptitude section.
- Input-output reasoning for SBI PO — the Mains reasoning format that sits next to coding-decoding in the SBI PO paper.
- IBPS Clerk coding-decoding mock test 01 — timed coding-decoding practice at IBPS Clerk level.
- IBPS PO coding-decoding mock test 01 — timed coding-decoding practice at IBPS PO level.
- SBI PO coding-decoding mock test 01 — timed coding-decoding practice at SBI PO level.
Sources: SBI PO Mains, IBPS PO Mains, IBPS Clerk Mains, SBI Clerk Mains and IBPS RRB Mains Reasoning exam patterns as published in their official notifications; coding-decoding conventions as followed in Indian bank exam answer keys. All 20 questions are original, written for this page, and every code was recomputed in Python from its stated rule. As of 6 November 2026.