Q.In a certain language, if BLOWN is coded as BLNOW then how will RIGHT be coded?

Coding-Decoding: The Art of Hidden Messages

Imagine you and a friend invent a secret language. Instead of saying "APPLE", you agree to say "BQQMF" — each letter shifted forward by one. Your friend hears "BQQMF" and knows instantly you mean apple. That's coding. Your friend reversing the shift to get back "APPLE" is decoding.

Coding-decoding problems in exams are exactly this: you are given a rule (the "code") that transforms words, letters, or numbers into something else. Your job is to either apply that rule to a new word, or figure out the rule from examples and then decode.

The Core Idea

Every coding problem has three parts:

1. The original — what you start with (e.g., a word like "CAT")
2. The code — the transformation rule (e.g., "each letter is replaced by the next letter in the alphabet")
3. The coded form — the result (e.g., "DBU")

You are given two of these three, and you must find the third.

The Most Common Patterns

1. Letter Shifting (Forward/Backward)

Each letter moves a fixed number of steps in the alphabet.

Example: If "GOOD" is coded as "HPPE", what is "FINE"?

Notice G→H (+1), O→P (+1), O→P (+1), D→E (+1). Every letter shifts forward by 1. So "FINE" becomes "GJOF".

2. Reversal

The word is simply written backwards.

Example: If "RAT" is coded as "TAR", then "MOON" is coded as "NOOM".

3. Position-Based Coding

Letters are replaced by their position numbers, or numbers are replaced by letters.

Example: If "BAT" is coded as "2120", then B=2, A=1, T=20. So "CAT" would be "3120".

4. Opposite Letters

Each letter is replaced by its "opposite" in the alphabet: A↔Z, B↔Y, C↔X, etc. (A + Z = 27, B + Y = 27, etc.)

Example: If "WAR" is coded as "DZI", then W(23)→D(4) because 23+4=27, A(1)→Z(26), R(18)→I(9).

5. Mixed Operations

Sometimes the rule combines shifting, reversing, and position changes. For example: "reverse the word, then shift each letter forward by 2."

How to Approach Any Problem

Step 1: Compare the original and the coded form. Write them one above the other, letter by letter. Look for a pattern.

Step 2: Check simple patterns first. Is it just shifting? Reversal? Opposite letters? Position numbers?

Step 3: If the pattern isn't obvious, write alphabet positions. Often the relationship is numerical (add 3, subtract 5, etc.).

Step 4: Test your guessed rule on the given example. If it works for all letters, apply it to the new word.

A Worked Example

Problem: In a certain code, "PENCIL" is written as "RGP EKN". How is "PAPER" written?

Step 1: Write them aligned:

P E N C I L
R G P   E K N

The coded form "RGP EKN" is two groups of three letters. The original "PENCIL" has 6 letters, so the code splits the word into two halves: "PEN" and "CIL".

Step 2: Compare first half: P→R (+2), E→G (+2), N→P (+2). Second half: C→E (+2), I→K (+2), L→N (+2). Every letter shifts forward by 2.

Step 3: Apply to "PAPER". Split into "PAP" and "ER". Shift each: P→R, A→C, P→R gives "RCR". E→G, R→T gives "GT". So the answer is "RCR GT".

Why This Matters

Coding-decoding tests your ability to recognize patterns and apply rules consistently — a skill that appears across mathematics, science, and logic. The problems look like puzzles, but they train your brain to think step-by-step, check assumptions, and avoid jumping to conclusions.

Start with the simplest possible rule. If it fits, use it. If not, add one layer at a time. That's the entire method.