It looks like you want the content rewritten, corrected, and made consistent. The main issues are:

• Some examples have ambiguous or incorrect reasoning.
• A few rules are inconsistent (e.g., keyboard symbol patterns, matrix letter rule).
• Wording can be clearer and more suitable for aptitude preparation.

Below is a cleaned-up version.

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1. Alphanumeric Hybrid Codes

Idea

Identify separate patterns for the letters and the numbers in each term.

Rule

• Determine the rule for the letters (forward/backward shift, alternating shift, etc.).
• Determine the rule for the numbers (Arithmetic Progression, Geometric Progression, squares, etc.).
• Apply both rules independently.

Example 1

Problem: Find the next term.

A2, C5, E8, G11, ?

Solution

Step 1: Separate letters and numbers.

Letters: A, C, E, G

Numbers: 2, 5, 8, 11

Step 2: Letter pattern

A → C → E → G (+2 each time)

Next letter = I

Step 3: Number pattern

2 → 5 → 8 → 11 (+3 each time)

Next number = 14

Answer: I14

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Example 2

Problem: Find the next term.

Z10, X9, V8, T7, ?

Solution

Letters decrease by 2:

Z → X → V → T → R

Numbers decrease by 1:

10 → 9 → 8 → 7 → 6

Answer: R6

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2. Code-to-Series Mapping

Idea

Convert letters into numerical positions (A=1, B=2, …, Z=26), identify the pattern, then convert back to letters.

Rule

1. Convert letters to numbers.
2. Identify the sequence.
3. Convert the result back to letters.

Example 1

Problem: Find the next code.

AB, DE, GH, JK, ?

Solution

AB = (1,2)

DE = (4,5)

GH = (7,8)

JK = (10,11)

Each position increases by 3.

Next pair:

13,14 = MN

Answer: MN

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Example 2

Problem: Find the next code.

AA, BD, CG, DJ, ?

Solution

First letters:

A, B, C, D (+1)

Next = E

Second letters:

A, D, G, J (+3)

Next = M

Answer: EM

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3. Position-Value Transformations

Idea

Each word is assigned a value using alphabet positions.

Rule

Common coding methods include:

• Sum of letter positions
• Reverse alphabet positions
• Difference of positions
• Product of positions

Example 1

Problem

If

CAT = 24

DOG = 26

(A=1, B=2, …, Z=26)

Find the coding rule.

Solution

CAT

C = 3

A = 1

T = 20

3 + 1 + 20 = 24

DOG

D = 4

O = 15

G = 7

4 + 15 + 7 = 26

Therefore,

Coding Rule = Sum of alphabet positions.

Answer: Sum of letter positions.

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Example 2

Problem

Using reverse positions

A = 26

B = 25

…

Z = 1

Find CAT.

Solution

C = 24

A = 26

T = 7

24 + 26 + 7 = 57

Answer: 57

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4. Matrix Coding Sequences

Idea

Identify row-wise or column-wise relationships to determine the missing element.

Rule

Look for operations such as:

• Addition
• Multiplication
• Difference
• Alphabet progression

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Example 1

Problem

3	5	8
6	10	?
9	15	24

Solution

Each row follows:

Third number = First + Second

6 + 10 = 16

Answer: 16

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Example 2

Problem

2A	4C	6E
3B	6D	?
4C	8F	12I

Solution

Number pattern:

• Row 1: 2, 4, 6
• Row 2: 3, 6, 9
• Row 3: 4, 8, 12

Missing number = 9

Letter pattern:

A, C, E (+2)

B, D, F (+2)

C, F, I (+3)

Thus Row 2 continues:

B → D → F

Missing element = 9F

Answer: 9F

Note: The original answer (9G) was inconsistent with the stated pattern.

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5. Chinese Coding

Idea

Determine the code for each word by comparing common words across coded sentences.

Rule

1. Identify common words.
2. Match them with common codes.
3. Decode remaining words.

Example

“sun is bright” → ti pi ro

“moon is cool” → pi so ki

“bright moon glows” → ro ki fu

Find:

sun glows cool

Solution

“is” = pi

“bright” = ro

“moon” = ki

Therefore

“sun” = ti

“glows” = fu

“cool” = so

Answer: ti fu so

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6. Machine Input-Output

Idea

Each step applies a fixed transformation to the input until the final output is reached.

Rule

Possible operations include:

• Sorting
• Swapping
• Rearranging
• Arithmetic transformation

Example 1

Input

42 18 35 27 51

Sort in ascending order.

Steps

42 18 35 27 51

18 35 27 42 51

18 27 35 42 51

Answer

18 27 35 42 51

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Example 2

Input

cat bat rat mat

Arrange alphabetically.

Steps

bat cat rat mat

bat cat mat rat

Answer

bat cat mat rat

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7. Binary Coding

Idea

Convert letters into binary using their alphabetical positions.

Rule

1. Convert letters to numbers.
2. Convert numbers into binary using the required bit length.
3. Join the binary values.

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Example 1

Problem

Encode ABC using 4-bit binary.

A = 1 = 0001

B = 2 = 0010

C = 3 = 0011

Answer

0001 0010 0011

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Example 2

Problem

Encode CAT using 5-bit binary.

C = 3 = 00011

A = 1 = 00001

T = 20 = 10100

Answer

00011 00001 10100

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8. Symbol Coding & Sentence Coding

Idea

Each word or phrase is represented by a fixed symbol or code.

Rule

Replace each word with its corresponding symbol while maintaining the sentence order.

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Example 1

Problem

@ = hello

= world

$ = good

% = morning

Find the codes for:

• good world
• hello morning

Solution

good → $

world → #

hello → @

morning → %

Answer

• good world → $ #
• hello morning → @ %

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Example 2

Problem

“red circle” = sun

“blue triangle” = shines

Decode:

“The red circle blue triangle”

Solution

Replace coded phrases:

The → The

red circle → sun

blue triangle → shines

Answer

The sun shines

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This revised version corrects inconsistencies (especially the Matrix Coding example), improves clarity, standardizes formatting, and makes the material more suitable for competitive aptitude exams such as SSC, Banking, UPSC, CAT, and placement tests.