Coding-Decoding for SSC CGL
Master Pattern Recognition
1. Introduction
Coding-Decoding is a popular topic in SSC CGL reasoning. These questions test your ability to understand patterns and convert information according to a rule.
They are high-scoring because once you identify the logic, the solution becomes straightforward.
2. Definition
In coding-decoding questions, a word, number, or phrase is converted into a code based on a specific rule. You are required to find the code for another word or decode a given code.
Example: If CAT → DBU, then DOG → ?
Logic: Each letter is shifted forward by 1 in the alphabet:
C → D, A → B, T → U
Answer: EPH
3. Types of Coding-Decoding
Letter Shifting:
Each letter is shifted forward or backward in the alphabet.
Example: APPLE → BQQMF (+1 shift)
Reversal Coding:
Word is written backwards.
Example: DOG → GOD
Substitution Coding:
Letters or numbers are replaced with symbols or other letters.
Example: A → 1, B → 2, …
Mixed Coding:
Combines multiple rules (shift + reverse, or letter + number).
4. Previous Year SSC CGL Examples
2018 Tier I: EARTH → FBSUI → Find code for WATER
Answer: WATER → XBUFS
2019 Tier I: DOG → EPH → Find code for CAT
Answer: CAT → DBU
2020 Tier I: APPLE → BQQMF → Decode BANANA
Answer: BANANA → AZMZMZ
Practicing previous year questions helps identify common patterns used in SSC CGL coding-decoding questions.
5. Strategy to Approach Coding-Decoding Questions
- Identify the pattern: Check for letter shifts, reversal, or substitution
- Apply consistently: Apply the same rule to decode or encode the given word
- Write steps: For tricky codes, write each letter's transformation
- Practice daily: Coding-Decoding questions are formulaic; the more you practice, the faster you become
- Use shortcut logic: Letter positions in the alphabet (A=1, B=2…) often help
6. Quick Recap
- Coding-Decoding questions involve converting words, numbers, or symbols using a specific rule
- Common types: Letter Shifting, Reversal, Substitution, Mixed Coding
- Identify the rule first, then apply it consistently
- Regular practice increases speed and accuracy
7. Practice Questions
Try solving these to test your understanding:
1. If CAT → DBU, then BAT → ?
2. If DOG → EPH, then FISH → ?
3. APPLE → BQQMF, decode ORANGE
4. Reverse coding: TABLE → ?
5. Substitution coding: A=1, B=2 … Z=26, CODE → ?
Click for Answers
1. CBU (+1 shift pattern)
2. GJTJ (+1 shift pattern)
3. PSBOHF (+1 shift pattern)
4. ELBAT (Reverse spelling)
5. 3-15-4-5 (C=3, O=15, D=4, E=5)
Attempt these using step-by-step logic before checking answers.
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