5.3 Coding-Decoding (Coded Statements & Mains Patterns)

Coding-Decoding: Prelims & Mains Patterns

Coding-Decoding tests a candidate's ability to decipher hidden structural rules governing transformations between plaintext words and ciphertext symbols, letters, and numbers. In the SBI PO Preliminary examination, coding questions typically follow the Substitution Coding model. In the Mains examination, questions shift to Advanced Multi-Element Pattern Coding (Symbol-Letter-Number triples), Conditional Matrix Coding, or Clock/Binary Coding.

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Prelims Substitution Coding (Elimination Technique)

In substitution coding, four or five sentences are provided alongside their coded equivalents. The words and codes are not in one-to-one positional order. The goal is to determine the exact code for individual words by comparing statements.

Step-by-Step Elimination Protocol

Consider the following sample set:

1. "financial market stability high" $\implies$ ka pa jo ta
2. "high inflation rate market" $\implies$ ta pa ma li
3. "financial growth rate steady" $\implies$ jo ma su zi

• Step 1 (Compare Line 1 and Line 2): Common words are "market" and "high". Common codes are pa and ta. Therefore, {"market", "high"} $\implies$ {pa, ta}.
• Step 2 (Compare Line 1 and Line 3): Common word is "financial". Common code is jo. Therefore, "financial" = jo.
• Step 3 (Deduce "stability"): In Line 1, the remaining word after removing "market", "high", and "financial" is "stability". The remaining code is ka. Therefore, "stability" = ka.
• Step 4 (Compare Line 2 and Line 3): Common word is "rate". Common code is ma. Therefore, "rate" = ma.
• Step 5 (Deduce Remaining Words): From Line 2, "inflation" = li. From Line 3, "growth steady" $\implies$ su zi (undetermined).

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Mains Advanced Pattern Coding (Symbol-Letter-Number)

In Mains exams, coding logic is applied word-by-word based on intrinsic properties of each word. Codes are typically formatted as a three-element combination, such as #G07, @L09, or $T20.

Element Breakdown & Common Patterns

   [ SYMBOL ]                [ LETTER ]               [ NUMBER ]
   (e.g., # or @)            (e.g., G or L)           (e.g., 07 or 09)
        |
  Defined by:               Defined by:              Defined by:
  - Word Length (Even/Odd)  - First Letter           - Total Letter Count
  - Vowel Count (1, 2, 3+)  - Last Letter            - First Letter Pos. Value
  - First Letter Category   - Opposite of Last       - Last Letter Pos. Value
  - Last Letter Type        - Second Vowel           - Vowel/Consonant Sum

1. Letter Logic Patterns

• First Letter of Word: "BANKING" $\implies$ B
• Last Letter of Word: "BANKING" $\implies$ G
• Reverse/Opposite of First/Last Letter: Reverse of first letter 'B' $\implies$ Y (where A\leftrightarrow Z, B\leftrightarrow Y, C\leftrightarrow X, D\leftrightarrow W, E\leftrightarrow V, F\leftrightarrow U, G\leftrightarrow T, H\leftrightarrow S, I\leftrightarrow R, J\leftrightarrow Q, K\leftrightarrow P, L\leftrightarrow O, M\leftrightarrow N).
• Second Letter from Left/Right: "BANKING" $\implies$ A or N.

2. Number Logic Patterns

• Total Word Length: "BANKING" (7 letters) $\implies$ 07
• Alphabetical Position of First/Last Letter: First letter 'B' $\implies$ 02; Last letter 'G' $\implies$ 07.
• Sum of Digits of Word Length: 7 letters $\implies$ 07.
• Count of Consonants / Vowels: 5 consonants, 2 vowels $\implies$ 05 or 02.
• Total Letters Multiplied by Constant: $7 \times 2 = 14$.

3. Symbol Logic Patterns

• Based on Word Length: Even length $\implies$ @; Odd length $\implies$ #.
• Based on Starting Letter: Starts with Vowel $\implies$ $; Starts with Consonant $\implies$ %.
• Based on Total Vowels: 1 Vowel $\implies$ !; 2 Vowels $\implies$ &; 3+ Vowels $\implies$ *.

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Conditional Matrix Coding

In Conditional Matrix questions, a table maps numbers/letters to base symbols, followed by a set of numbered conditional rules. You must apply these rules in strict hierarchy.

Sample Conditional Rules Setup

Rules:

1. Rule 1: If the first element is a vowel and the last element is a consonant, swap their codes.
2. Rule 2: If both the first and last elements are vowels, code both elements as &.
3. Rule 3: If an even number is immediately preceded and immediately followed by a consonant, code the even number as X.

[!IMPORTANT] Always apply rules sequentially from Rule 1 to Rule N. If a rule condition is met, modify the string accordingly before testing subsequent rules unless specified that rules are mutually exclusive.

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Step-by-Step Worked Example

Given Coded Lines:

• "FINANCIAL SYSTEM STABILITY" $\implies$ @L09 #M06 @Y09
• "BANKING CAPITAL ASSETS" $\implies$ #G07 #L07 $S06

Task: Determine the logic and find the code for "ECONOMIC".

Pattern Deduction Steps

1. Analyze Numbers:
   • "FINANCIAL" (9 letters) $\implies$ 09
   • "SYSTEM" (6 letters) $\implies$ 06
   • "STABILITY" (9 letters) $\implies$ 09
   • Deduction: Number = Total letter count formatted as 2 digits.
2. Analyze Letters:
   • "FINANCIAL" (Last letter L) $\implies$ L
   • "SYSTEM" (Last letter M) $\implies$ M
   • "STABILITY" (Last letter Y) $\implies$ Y
   • Deduction: Letter = Last letter of the word.
3. Analyze Symbols:
   • "FINANCIAL" (Starts with F - Consonant, Length 9 - Odd) $\implies$ @
   • "SYSTEM" (Starts with S - Consonant, Length 6 - Even) $\implies$ #
   • "BANKING" (Starts with B - Consonant, Length 7 - Odd) $\implies$ #
   • "ASSETS" (Starts with A - Vowel, Length 6 - Even) $\implies$ $
   • Deduction: Starts with Vowel $\implies$ $; Starts with Consonant + Even Length $\implies$ #; Starts with Consonant + Odd Length $\implies$ @.

Encoding "ECONOMIC"

• Starting Character: 'E' (Vowel) $\implies$ Symbol is $.
• Last Letter: 'C' $\implies$ Letter is C.
• Total Length: 8 letters $\implies$ Number is 08.

Final Code for "ECONOMIC": $C08