Coding Decoding
✏️ Practice with curated questions covering all difficulty levels. Detailed solutions and expert tips help you master each question type.
Sample Questions
Study MaterialCoding Decoding – Sample Questions
Coding Decoding questions in competitive examinations are generally based on alphabet positions, letter shifting, reverse coding, number coding, symbol coding, conditional coding, substitution logic, and fictitious language analysis. Practicing different varieties of questions improves logical reasoning speed and pattern-recognition ability.
The following fully solved sample questions cover the most important Coding Decoding patterns frequently asked in SSC, Banking, Railway, Insurance, Defence, State PSC, and aptitude examinations.
Sample Question 1 – Simple Letter Shifting
If CAT is coded as DBU, then how will DOG be coded?
- EPH
- EOG
- FPH
- EOH
Solution
- C → D (+1)
- A → B (+1)
- T → U (+1)
- Apply the same logic to DOG.
- D → E
- O → P
- G → H
Answer: EPH
Sample Question 2 – Reverse Coding
If TIME is coded as EMIT, then how will ROAD be coded?
- DAOR
- RAOD
- DOAR
- ADOR
Solution
- The word TIME is written in reverse order.
- Apply the same logic to ROAD.
- ROAD → DAOR
Answer: DAOR
Sample Question 3 – Alphabet Position Coding
If the code of BAT is obtained by adding alphabet positions, what is the code of BAT?
- 21
- 23
- 25
- 27
Solution
- B = 2
- A = 1
- T = 20
- Total = 2 + 1 + 20 = 23
Answer: 23
Sample Question 4 – Alternate Letter Pattern
If GOOD is coded as HNPE, then how is BAD coded?
- CBE
- CZD
- CAD
- BCE
Solution
- Observe the pattern carefully.
- Letters are shifted alternately.
- B → C (+1)
- A → Z (−1)
- D → E (+1)
Answer: CZE
Sample Question 5 – Backward Alphabet Coding
If A = 26, B = 25, C = 24 and so on, then what is the code for DOG?
- 23, 12, 20
- 24, 13, 21
- 23, 15, 20
- 22, 12, 21
Solution
- Backward Position Formula = 27 − Forward Position
- D = 27 − 4 = 23
- O = 27 − 15 = 12
- G = 27 − 7 = 20
Answer: 23, 12, 20
Sample Question 6 – Symbol Coding
If:
A → #
B → %
C → @
Then what is the code for CAB?
- @#%
- #@%
- %#@
- @%#
Solution
- C → @
- A → #
- B → %
Answer: @#%
Sample Question 7 – Circular Alphabet Coding
If each letter is shifted one step forward in a circular alphabet series, then what is the code for ZEBRA?
- AFCSB
- AFDRA
- BFCSB
- AFCRB
Solution
- Z → A
- E → F
- B → C
- R → S
- A → B
Answer: AFCSB
Sample Question 8 – Fictitious Language Coding
In a certain code language:
“sky is blue” → 481
“sea is deep” → 246
What is the code for “is”?
- 2
- 4
- 6
- 8
Solution
- Common word in both sentences = “is”
- Common code in both code groups = 4
- Therefore code for “is” = 4
Answer: 4
Sample Question 9 – Substitution Coding
If RED is called BLUE, BLUE is called GREEN, and GREEN is called YELLOW, then what is the color of the sky in that code language?
- GREEN
- BLUE
- YELLOW
- RED
Solution
- The actual color of the sky is BLUE.
- BLUE is called GREEN in the code language.
Answer: GREEN
Sample Question 10 – Conditional Coding
In a certain code language:
- If a word starts with a vowel, add 1 to every letter.
- If a word starts with a consonant, subtract 1 from every letter.
How will APPLE be coded?
- BQQMF
- ZOOKD
- BPPMF
Solution
- APPLE starts with a vowel.
- Shift every letter one step forward.
- A → B
- P → Q
- P → Q
- L → M
- E → F
Answer: BQQMF
Sample Question 11 – Odd-Even Position Coding
If letters at odd positions are shifted +1 and letters at even positions are shifted −1, then how will CODE be written?
- DNCF
- DNDD
- DNCE
- BPCF
Solution
- C → D (+1)
- O → N (−1)
- D → E (+1)
- E → D (−1)
Answer: DNED
Sample Question 12 – Mixed Coding Pattern
If STAR is coded as UVCT, then how is MOON coded?
- OQQP
- NPPQ
- OQPP
- NPPO
Solution
- S → U (+2)
- T → V (+2)
- A → C (+2)
- R → T (+2)
- Apply the same logic to MOON.
- M → O
- O → Q
- O → Q
- N → P
Answer: OQQP
Quick Solving Tips
- Always check alphabet positions first.
- Look for forward or backward shifting patterns.
- Verify reverse arrangements carefully.
- Check odd-even letter positions.
- Find common words in fictitious language questions.
- Use elimination when multiple patterns seem possible.
Most Important Concepts Used in Questions
| Concept | Question Frequency |
|---|---|
| Letter Shifting | Very High |
| Alphabet Positions | Very High |
| Fictitious Language Coding | Very High |
| Conditional Coding | High |
| Number Coding | High |
| Symbol Coding | Moderate |
Final Takeaway
Most Coding Decoding questions can be solved quickly using alphabet analysis, letter shifting, common-word logic, pattern observation, and elimination techniques. Candidates who regularly practice different coding structures become highly efficient in solving Coding Decoding questions in competitive examinations.