Analytical structures, relational layouts, data dependencies, and logical deduction profiling module.
Logical Reasoning is designed to evaluate your ability to think critically, analyze structured data, interpret spatial arrangements, and apply reasoning methodologies under strict parameters.
This section focuses on testing your understanding of familial lineages, generational maps, and contextual relationships between items or concepts.
A. Blood Relations
Blood relation problems require decoding complex statements about family members to establish a direct relationship between two people.
Generation Mapping Matrix
To systematically solve blood relation problems, it is crucial to lay them out across generational levels:
- Generation I (Grandparents): Maternal/Paternal Grandfather, Grandmother.
- Generation II (Parents/In-laws): Father, Mother, Uncle, Aunt, Father-in-law, Mother-in-law.
- Generation III (Self & Peers): Self, Brother, Sister, Cousin, Husband, Wife, Brother-in-law, Sister-in-law.
- Generation IV (Children): Son, Daughter, Nephew, Niece.
Core Terminology Definitions
- Paternal vs. Maternal: Paternal refers to relationships through the father's side; maternal refers to relationships through the mother's side.
- Sibling vs. Cousin: Siblings share the same biological parents. Cousins are children of one's aunts or uncles.
- Spouse's Family (In-laws): * Brother-in-law: Spouse’s brother OR sister’s husband.
- Sister-in-law: Spouse’s sister OR brother’s wife.
- Niece vs. Nephew: Niece is a female child of one's brother or sister; Nephew is a male child of one's brother or sister.
Solved Examples
- Scenario-Based Question:
- Question: Pointing to a photograph, a man said, "I have no brother or sister but that man’s father is my father’s son." Whose photograph was it?
- Step-by-Step Breakdown:
- Analyze the statement: "my father's son".
- Since the speaker says "I have no brother or sister", his father's only son must be himself.
- Substitute this back into the sentence: "that man’s father is myself".
- Therefore, the man in the photograph is the speaker's son.
- Correct Answer: His son’s photograph.
- Coded Relationship Question:
- Question: If $A + B$ means $A$ is the brother of $B$; $A - B$ means $A$ is the sister of $B$; and $A \times B$ means $A$ is the father of $B$. Which of the following means $M$ is the nephew of $N$?
- (a) $N - K + M$ (b) $N \times K - M$ (c) $N - K \times M$ (d) $N + K \times M$ (where $M$ is male)
- Step-by-Step Breakdown:
- For $M$ to be a nephew, $M$ must be male and his parent must be a sibling of $N$.
- Look at option (c): $N - K \times M$. This means $N$ is the sister of $K$, and $K$ is the father of $M$. This makes $M$ the child of $N$'s brother. If $M$'s gender is specified as male, $M$ is the nephew of $N$.
- Correct Answer: (c) (given $M$ is verified as male).
B. Analytical & Conceptual Relations (Analogies)
Analogies test the ability to recognize a relationship between a primary pair of words/concepts and replicate that precise relationship in a secondary pair ($A : B :: C : D$).
Common Classification Relationships
- Worker & Tool: Carpenter : Saw :: Surgeon : Scalpel
- Cause & Effect: Pathogen : Disease :: Carelessness : Accident
- Product & Raw Material: Prism : Glass :: Jewelry : Gold
- Study & Topic (Ologies): Mycology : Fungi :: Paleontology : Fossils
- Part to Whole: Piston : Engine :: Sail : Ship
Classification exercises require examining a given set of terms, numbers, or configurations to identify the element that does not comply with the common underlying logical rule shared by the others.
A. Semantic/Word Classification
Words are grouped by exact semantic category, structural properties, or usage profiles.
Solved Examples
- Question: Identify the odd one out: Mercury, Venus, Earth, Moon, Mars.
- Logical Filter: Mercury, Venus, Earth, and Mars are biological/geological classifications of planets orbiting a star. The Moon is a natural satellite.
- Correct Answer: Moon.
- Question: Identify the odd one out: Aisles, Epilogue, Prologue, Preface, Chapter.
- Logical Filter: Epilogue, Prologue, Preface, and Chapter are structural components of a book. An aisle is a walkway feature found in theaters, planes, or churches.
- Correct Answer: Aisles.
B. Numeric Classification
Numbers are categorized based on mathematical properties such as prime factors, digital roots, perfect squares, cubes, or arithmetic progressions.
Common Rules to Test
- Prime vs. Composite numbers.
- Divisibility parameters (e.g., all numbers are divisible by 7 except one).
- Form patterns: $(n^2 + 1)$, $(n^3 - 1)$, or Fibonacci sequences.
Solved Examples
- Question: Find the odd number: $27, 64, 125, 144, 216$.
- Logical Filter: * $27 = 3^3$
- $64 = 4^3$
- $125 = 5^3$
- $216 = 6^3$
- $144 = 12^2$ (It is a perfect square, not a perfect cube).
- Correct Answer: 144.
Non-verbal reasoning utilizes spatial frameworks, shapes, and structural orientation patterns to evaluate abstract mental manipulation.
A. Spatial & Pattern Rotations
Shapes are systematically modified across a series of frames via specific transformations:
- Rotational Shifts: Clockwise (CW) or Counter-Clockwise (CCW) increments, typically in angles of $45^\circ$, $90^\circ$, or $180^\circ$.
- Inversion / Mirroring: Horizontal flips (lateral inversion) or vertical flips (water images).
B. Matrix Completion & Graphic Analogies
In a $3 \times 3$ matrix or an analogy pair ($A : B :: C : ?$), look for operations applied across rows or columns:
- Element Addition/Deletion: Lines or shading parameters are added or eliminated sequentially.
- Geometric Superimposition: Overlaying figure 1 onto figure 2 using boolean logic (e.g., lines that intersect/overlap are deleted, non-overlapping elements remain).
Solved Example
- Question: Figure $A$ is a solid shaded square. Figure $B$ is the same square, unshaded, with two internal diagonals drawn. If Figure $C$ is a solid shaded circle, what is Figure $D$?
- Logical Filter: The transformation rule from $A \to B$ is: Remove solid shading + Add internal intersection lines. Applying this rule to $C$ (shaded circle) yields an unshaded circle containing intersecting perpendicular diameters.
- Correct Answer: An open circle with an internal cross ($+$ or $\times$).
This domain tests your capacity to evaluate logical arguments and map step-by-step decision trees or algorithmic procedures. It is sub-divided into three strategic frameworks: Pure Logic, Common Sense Logic, and Guest Logic.
┌───────────────────────────┐
│ LOGICAL REASONING │
│ & DISCRETION FRAMEWORKS │
└─────────────┬─────────────┘
│
┌───────────────────────────────┼───────────────────────────────┐
▼ ▼ ▼
┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐
│ PURE LOGIC │ │ COMMON SENSE │ │ GUEST LOGIC │
│ Strict Deducts │ │ Practical Facts │ │ Approximations │
│ & Syllogisms │ │ & Realities │ │ & Probabilities │
└─────────────────┘ └─────────────────┘ └─────────────────┘
Syllogisms & Analytical Deductions
Pure logic operates inside a closed system. The validity of an argument depends entirely on its structure, independent of whether the statements reflect real-world facts.
Syllogistic Rules
- Statements: Contain Quantifiers (All, Some, No).
- Venn Diagram Verification: To check validity, draw the absolute minimum overlapping boundaries required by the premises. An argument is valid only if the conclusion holds true across all possible diagram configurations.
Solved Example
- Premises: 1. All architects are artists.
- 2. Some artists are structural engineers.
- Conclusions:
- I. Some architects are structural engineers.
- II. No architect is a structural engineer.
- Evaluation via Pure Logic: * Set 1: Architects ($A$) is completely enclosed inside Artists ($Ar$).
- Set 2: Structural Engineers ($E$) overlaps with Artists ($Ar$).
- Because $E$ can overlap $Ar$ without intersecting $A$, Conclusion I is not guaranteed. However, $E$ could overlap with $A$, so Conclusion II is also not guaranteed. Because they form a contradictory pair where one must structurally happen if the other does not, either I or II must follow.
- Correct Answer: Either Conclusion I or II follows.
Cause-and-Effect & Critical Assumptions
Unlike pure logic, Common Sense Logic relies on real-world knowledge, established physical laws, socio-economic dynamics, and human behavior.
Core Areas Tested
- Statement & Assumptions: An assumption is an unstated, implied premise that the speaker takes for granted when making a claim.
- Statement & Courses of Action: Evaluating practical, fair, and effective solutions to a presented problem. Solutions must directly address the issue without creating secondary complications.
Solved Example
- Statement: "The municipal corporation has warned citizens that consumption of water directly from open local wells during monsoons poses extreme health hazards."
- Proposed Courses of Action:
- I. The local wells should be permanently sealed and filled with concrete immediately.
- II. The corporation should arrange to test and disinfect the well water systems while providing alternative clean drinking channels during the season.
- Evaluation via Common Sense Logic: Action I is an extreme and impractical response that destroys a valuable water asset. Action II is a balanced, practical, corrective measure.
- Correct Answer: Only Course of Action II follows.
Guest Logic (often associated with business case interviews or open-ended analytical estimations) evaluates how you break down complex, ambiguous problems using logical assumptions, structured frameworks, and order-of-magnitude calculations.
Core Methodological Strategy
- Deconstruct the Objective: Break the large question into manageable, identifiable variables.
- Establish Base Assumptions: Use reasonable anchor numbers (e.g., standard populations, average lifespans, daily consumption limits).
- Apply a Structured Formula/Flow Chart: Calculate step-by-step to arrive at a logical estimate.
Solved Example
- Problem Statement: Estimate the total number of passenger cars active in a metropolitan city with a total population of 4 million people.
- Flow Chart and Logic Walkthrough:
- Step 1: Household Division: Assume an average household size of 4 people.
- $$\text{Total Households} = \frac{4,000,000}{4} = 1,000,000\text{ households}$$
- Step 2: Economic Stratification: Assume income distribution permits car ownership for a certain percentage of households:
- High/Upper-Middle Income (Can afford a car): $30\%$ of households = $300,000$ households.
- Lower-Middle/Low Income (Rely on public transit/two-wheelers): $70\%$.
- Step 3: Ownership Density: Within the $300,000$ capable households, assume an average of $1.2$ cars per household (accounting for some families owning multiple vehicles).
- $$\text{Total Estimated Cars} = 300,000 \times 1.2 = 360,000\text{ cars}$$
- Conclusion: A logically derived estimate for active passenger cars in the city is approximately $360,000$.