Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples - Aptitude Questions & Answers
Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples is one of the most important topics in Logical Reasoning Explained: Concepts, Tricks, and Practice Questions. In this lesson, you will learn concepts, formulas, shortcuts, solved examples, and aptitude questions with answers. This topic is useful for exams like SSC, Bank, CAT, TCS, and other competitive exams.
Mastering Series and Coding problems is crucial for logical reasoning sections in competitive exams. This comprehensive guide covers everything from basic number patterns to complex coded language problems, with clear patterns, examples, and step-by-step solutions for each type of series and coding problem.
Series & Coding: Complete Guide with Patterns & Examples
What are Series and Coding Problems?
Series problems involve identifying patterns in sequences of numbers or letters. Coding problems involve converting information from one form to another using specific rules. Both test logical thinking, pattern recognition, and analytical skills.
Problem Solving Preference Order
| Priority | Pattern Type | Examples |
|---|---|---|
| 1 | Addition/Subtraction | +3, -2, +4, -1 patterns |
| 2 | Multiplication/Division | ×2, ÷3, ×1.5 patterns |
| 3 | Special Number Types | Prime, Square, Cube, Fibonacci |
| 4 | Multiple Operations | Alternating patterns, combined operations |
1. Number Series
Understanding Number Series
A number series is a sequence of numbers arranged in a specific order or pattern. Each number follows certain rules based on arithmetic operations or mathematical functions. The goal is to identify the pattern and find missing or next numbers.
Common Number Series Patterns
Arithmetic Series
Pattern: +3 each time
Geometric Series
Pattern: ×2 each time
Prime Numbers
Pattern: Prime numbers
Square/Cube
Pattern: n² sequence
Number Series Problems
Problem 1: Simple Addition Pattern
Question: Find the next term: 4, 7, 10, 13, ?
Solution:
Pattern: Add 3 to each term
13 + 3 = 16
Problem 2: Decreasing Subtraction Pattern
Question: Find the next term: 43, 42, 40, 37, 33, ?
Solution:
Pattern: Subtract increasing numbers (1, 2, 3, 4...)
33 - 5 = 28
Problem 3: Multiplication Pattern
Question: Find the next term: 2, 4, 12, 48, ?
Solution:
Pattern: Multiply by increasing numbers (2, 3, 4...)
48 × 5 = 240
Problem 4: Prime Number Addition
Question: Find the next term: 4, 7, 12, 19, 30, ?
Solution:
(prime)
(prime)
(prime)
(prime)
(prime)
Pattern: Add consecutive prime numbers (3, 5, 7, 11...)
Next prime after 11 is 13
30 + 13 = 43
Problem 5: Alternating Pattern
Question: Find the next term: 3, 2, 4, 3, 6, 5, ?
Solution:
Group as pairs: (3,2), (4,3), (6,5), (?)
Pattern: Subtract 1, then multiply by 2
5 × 2 = 10
Problem 6: Increasing Addition
Question: Find missing term: 5, 15, 26, ?, 51, 65
Solution:
Pattern: Add increasing numbers (10, 11, 12, 13, 14)
26 + 12 = 38
2. Alphabet Series
Understanding Alphabet Series
An alphabet series is a sequence of letters following specific patterns based on their positions in the alphabet (A=1, B=2... Z=26). Patterns can involve skipping letters, reversing order, or using numerical increments.
Alphabet Position Reference
Alphabet Series Problems
Problem 1: Triple Letter Pattern
Question: Find next term: MAB, NCD, OEF, ?
Solution:
Pattern: Each letter increases by specific amounts:
- 1st letter: +1 position (M→N→O→P)
- 2nd letter: +2 positions (A→C→E→G)
- 3rd letter: +2 positions (B→D→F→H)
O(15) +1 = P(16)
E(5) +2 = G(7)
F(6) +2 = H(8)
Problem 2: Skip Pattern
Question: Find next term: ACE, FHJ, KMO, ?
Solution:
- A(1) +5 = F(6)
- C(3) +5 = H(8)
- E(5) +5 = J(10)
Continue pattern: K(11)+5=P(16), M(13)+5=R(18), O(15)+5=T(20)
Problem 3: Mixed Letters & Numbers
Question: Find missing term: M4A, NB7, O5C, PD6, ?, RF5
Solution:
| Term | 1st Letter | Number | 3rd Letter |
|---|---|---|---|
| M4A | M | 4 | A |
| NB7 | N | 7 | B |
| O5C | O | 5 | C |
| PD6 | P | 6 | D |
| ? | ? | ? | ? |
| RF5 | R | 5 | F |
Patterns:
- Letters: Increase by 1 each time
M→N→O→P→Q→R
A→B→C→D→E→F - Numbers: Alternate +1 and -1 pattern
4→7→5→6→?→5
Pattern: 4(+3)→7(-2)→5(+1)→6(-1)→5(-1)→5
Missing term: Q (after P), 5 (6-1), E (after D)
Problem 4: Decreasing Pattern
Question: Find next term: ZY, WV, TS, QP, ?
Solution:
Pattern: Each term derived from previous:
- Z(26) -1 = Y(25)
- Y(25) -2 = W(23), W -1 = V(22)
- V(22) -2 = T(20), T -1 = S(19)
- S(19) -2 = Q(17), Q -1 = P(16)
- P(16) -2 = N(14), N -1 = M(13)
3. Odd Man Out
Understanding Odd Man Out
The Odd Man Out is an element in a series that doesnt follow the same pattern or share the same characteristics as the others. It stands out because it breaks the established rule.
Common Odd Man Out Patterns
Number Properties
- Even among odds
- Prime among composites
- Square among non-squares
- Multiple of specific number
Alphabet Patterns
- Wrong position jumps
- Different vowel/consonant
- Wrong pattern continuation
- Different category
Word Categories
- Different part of speech
- Different meaning category
- Different origin/language
- Different usage
Odd Man Out Problems
Problem 1: Number Pattern
Question: Find the odd one: 10, 20, 40, 51, 60
Solution:
Pattern: All numbers are multiples of 10 except 51
- 10 = 10 × 1
- 20 = 10 × 2
- 40 = 10 × 4
- 51 = NOT multiple of 10
- 60 = 10 × 6
Problem 2: Alphabet Pattern
Question: Find the odd one: ADH, BEI, CFM, DGK
Solution:
| Term | Pattern | Correct Sequence | Given | Status |
|---|---|---|---|---|
| ADH | A→D(+3), D→H(+4) | A(1), D(4), H(8) | ADH | ✓ Correct |
| BEI | B→E(+3), E→I(+4) | B(2), E(5), I(9) | BEI | ✓ Correct |
| CFM | C→F(+3), F→J(+4) | C(3), F(6), J(10) | CFM | ✗ Wrong (M=13, not J=10) |
| DGK | D→G(+3), G→K(+4) | D(4), G(7), K(11) | DGK | ✓ Correct |
4. Analogy
Understanding Analogy
Analogy involves finding relationships between pairs of items and identifying similar relationships in other pairs. It tests understanding of relationships and pattern application.
Types of Analogies
Number Analogy
Pattern: Each digit +3
Alphabet Analogy
Pattern: Reverse order
Word Analogy
Pattern: Habitat relationship
Instrument Analogy
Pattern: Measurement relationship
Analogy Problems
Problem 1: Number Analogy
Question: 345 : 678 :: 261 : ?
Solution:
2 + 3 = 5
6 + 3 = 9
1 + 3 = 4
Problem 2: Alphabet Analogy
Question: ABC : ZYX :: GHI : ?
Solution:
G(7) → T(20) [27-7]
H(8) → S(19) [27-8]
I(9) → R(18) [27-9]
Formula: Opposite letter = 27 - position
Problem 3: Word Relationship
Question: Fish : Water :: Bird : ?
Solution:
Relationship: Animal and its natural habitat
Fish lives in water, Bird lives in air
Problem 4: Instrument Relationship
Question: Speedometer : Speed :: Odometer : ?
Solution:
Relationship: Instrument and what it measures
Speedometer measures speed, Odometer measures distance
5. Coded Language
Understanding Coding & Decoding
Coding means converting words, numbers, or letters into a special form using rules. Decoding is reversing this process to find the original form. These problems test pattern recognition and logical application of rules.
Types of Coding Problems
Letter to Letter
Each letter replaced by another
Letter to Number
Letters assigned number codes
Word Coding
Words assigned code words
Mixed Coding
Letters, numbers, symbols mixed
Coding Problems
Problem 1: Letter to Letter Coding
Question: If (COMPUTER) is written as (DPNQVUFS), how is (LAPTOP) written?
Solution:
| Original | C | O | M | P | U | T | E | R |
|---|---|---|---|---|---|---|---|---|
| Coded | D | P | N | Q | V | U | F | S |
| Pattern | +1 | +1 | +1 | +1 | +1 | +1 | +1 | +1 |
Pattern: Each letter shifted forward by 1 position
LAPTOP → Apply same pattern:
L+1=M, A+1=B, P+1=Q, T+1=U, O+1=P, P+1=Q
Problem 2: Letter to Number Coding
Question: If GRAPH=23156, NOTE=4078, how is PHONE coded?
Solution:
PHONE = P(5) H(6) O(0) N(4) E(8)
Problem 3: Word Coding
Question: (gim tol sim) = (what is this), (dak gim sim) = (who is this). Code for (what)?
Solution:
Common words:(is) and (this) appear in both
Common codes: (gim) and (sim) appear in both
Therefore: (gim sim) = (is this)
In first sentence: (tol) must be (what)
Problem 4: Number to Letter Coding
Question: 2431 = RMNO, 05678 = HICAG. How is 7260 written?
Solution:
7260 = 7(A) 2(R) 6(C) 0(H)
Problem Solving Tips
Number Series
- Check difference between terms
- Check ratio between terms
- Look for square/cube patterns
- Check prime numbers
- Group terms if needed
Alphabet Series
- Convert letters to positions
- Look for constant differences
- Check reverse patterns
- Consider vowel/consonant patterns
- Group letters if in sets
Coding Problems
- Find pattern in given examples
- Look for common elements
- Apply pattern consistently
- Verify with all given data
- Check reverse if needed
General Approach
- Start with simplest pattern
- Work systematically
- Verify with all terms
- If stuck, try different approaches
- Practice common patterns
Frequently Asked Questions
Whats the priority order for number series patterns?
1) Addition/Subtraction, 2) Multiplication/Division, 3) Special numbers (primes, squares), 4) Multiple operations. Always try simpler patterns first.
How to handle alphabet series with numbers mixed in?
Separate letters and numbers. Analyze each sequence independently. Look for patterns in letter positions and number sequences separately, then combine.
What if multiple patterns seem possible in a series?
Use the preference order. Check which pattern works for all given terms. The correct pattern must work consistently for the entire series, not just part of it.
How to solve word coding problems efficiently?
Look for common words and common codes in multiple sentences. Eliminate known codes to find unknown ones. Start with words that appear most frequently.
Whats the quickest way to find odd man out?
Look for the element that breaks the most obvious pattern. Check number properties (even/odd, prime/composite), alphabetical patterns, or category mismatches.
How to verify my answer in analogy problems?
The relationship in the answer pair must be exactly the same as in the given pair. Test if the same rule/relationship applies perfectly to both pairs.
Frequently Asked Questions
What is Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples?
Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples is an important aptitude topic used in competitive exams that tests your logical reasoning and problem-solving abilities.
Is Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples important for competitive exams?
Yes, Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples is frequently asked in SSC, Bank, CAT, TCS, and other placement exams. It's essential to master this topic for better scores.
How to prepare Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples easily?
Practice solved examples, learn formulas and shortcuts, and attempt practice questions regularly to master Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples.
What are the important formulas in Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples?
Key formulas vary by topic, but generally include basic concepts, shortcuts, and standard problem-solving approaches specific to Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples.
How many questions come from Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples?
Typically 5-10 questions come from Series, Analogy & Coding-Decoding: Concepts, Tricks, and Solved Examples in most competitive exams, making it a high-scoring section.
Related Learning & Career Resources
Logical Reasoning Explained: Concepts, Tricks, and Practice Questions Aptitude Questions
Practice all Logical Reasoning Explained: Concepts, Tricks, and Practice Questions aptitude questions with answers and shortcuts.
Logical Reasoning Explained: Concepts, Tricks, and Practice Questions Interview Questions
Prepare HR & technical interview questions asked for freshers and experienced.
Latest Jobs After Aptitude Preparation
Apply for latest fresher & work-from-home jobs after aptitude practice.