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Coding-decoding practice questions for bank exams

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

A coding-decoding question shows how one word, number or symbol set is converted into a code, and asks you to apply the same rule to a new item. The rule can be a shift in the alphabet, a mirror image of the alphabet, a word-to-code match or a swap of arithmetic signs. The five questions below cover the four types most seen in bank-exam Reasoning.

Letter positions and mirror pairs

Memorise A = 1 up to Z = 26. The mirror of a letter at position n is the letter at position 27 − n.

Useful pattern types: constant shift (+2 on every letter), progressive shift (+1, +2, +3 ...), alternating shift (+1, −1, +1 ...), reversal of the word and position-value sums.

Five practice questions

Question 1

In a certain code, CASH is written as DCVL. How is LOAN written in that code?

• A. MPDQ
• B. MQDR
• C. MQER
• D. NQDR

Question 2

In a certain code, SYSTEM is written as HBHGVN. How is BRANCH written in that code?

• A. YIZMXS
• B. YJZMXS
• C. YIZNXS
• D. XIZMYS

Question 3

In a code language, "bank loan interest" is written as "ta pe ki", "loan rate fixed" is written as "ki mu re" and "interest rate cut" is written as "pe mu zo". What is the code for "bank"?

• A. pe
• B. ki
• C. mu
• D. ta

Question 4

If + means −, − means ×, × means ÷ and ÷ means +, what is the value of 24 ÷ 6 + 4 × 2 − 3?

• A. 18
• B. 24
• C. 30
• D. 36

Question 5

In a certain code, BANKING is written as CZOJJMH. How is CHENNAI written in that code?

• A. DIFMOZJ
• B. DGFNOZJ
• C. DGFMOZJ
• D. DGENOZJ

Answers and explanations

1. B. Compare CASH with DCVL: C to D is +1, A to C is +2, S to V is +3 and H to L is +4. Apply +1, +2, +3, +4 to LOAN: L becomes M, O becomes Q, A becomes D and N becomes R. The code is MQDR.
2. A. Compare SYSTEM with HBHGVN: S (19) becomes H (8), and 19 + 8 = 27. Every letter is replaced by its mirror letter. So B becomes Y, R becomes I, A becomes Z, N becomes M, C becomes X and H becomes S, giving YIZMXS.
3. D. The common code between the first two sentences is "ki", which stands for "loan". The common code between the first and third is "pe", which stands for "interest". The first sentence has the codes ta, pe and ki for bank, loan and interest, so "bank" must be "ta".
4. B. Replace each sign by its meaning: 24 ÷ 6 + 4 × 2 − 3 becomes 24 + 6 − 4 ÷ 2 × 3. Division and multiplication come first from the left: 4 ÷ 2 = 2, then 2 × 3 = 6. So 24 + 6 − 6 = 24.
5. C. Compare BANKING with CZOJJMH: the shifts are +1, −1, +1, −1, +1, −1, +1. Apply the same to CHENNAI: C becomes D, H becomes G, E becomes F, N becomes M, N becomes O, A becomes Z and I becomes J, giving DGFMOZJ.

How to prepare coding-decoding

• Write the letter positions under the letters. Seeing 3, 1, 19, 8 against 4, 3, 22, 12 shows the shift pattern at a glance.
• Test the three common patterns in order. Try a constant shift, then a progressive or alternating shift, then a mirror.
• For word codes, find the common code first. Two sentences that share one word share one code (Question 3).
• Rewrite operation codes first and calculate second. Make the substitution on paper before you apply BODMAS.
• Check with the given example. Before you code the new word, apply your rule to the sample to confirm it matches.
• Learn mirror pairs by heart. A–Z, B–Y and so on takes ten minutes and saves time on every mirror question.

A target of 45 seconds a question is realistic for letter codes. Word codes and operation codes take a little longer. For symbol-based logic in a different form, try inequality.

The full coding-decoding topic test is on PrepMatic (about 15 questions, 30 minutes). The Reasoning Ability guide and the bank exam hub show where this topic appears.

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