Revision Sheet 3

Never use:

Common Sense
Personal Knowledge
Real-World Facts

Use only:

Given Statements

Everything in this sheet follows this rule.

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1. SYLLOGISM

One of the most important logical reasoning topics.

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Basic Terms

All

Statement:

All Cats are Animals.

Meaning:

Cats ⊂ Animals

Diagram:

Animals

 (Cats)

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Some

Statement:

Some Cats are Black.

Meaning:

At least one.

Not necessarily all.

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No

Statement:

No Cats are Dogs.

Meaning:

Zero overlap.

Diagram:

(Cats)      (Dogs)

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Some Not

Statement:

Some Students are not Athletes.

Meaning:

At least one student lies outside the athlete group.

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Statement Type 1

Statement:

All A are B.

Diagram:

B

(A)

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Conclusions

All A are B       ✓ True
Some A are B      ✓ True
Some B are A      ✓ True
All B are A       ✗ False

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Most Common Trap

Statement:

All Doctors are Humans.

Students assume:

All Humans are Doctors.

Wrong.

The reverse is not guaranteed.

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Statement Type 2

Statement:

No A are B.

Diagram:

(A)      (B)

Conclusions:

No B are A       ✓ True
Some A are B     ✗ False

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Statement Type 3

Statement:

Some A are B.

Diagram:

(A ∩ B)

Conclusions:

Some B are A     ✓ True

Nothing else is guaranteed.

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Possibility Cases

Statement:

Some A are B.

Can we say:

All A are B.

Possible?

YES

Because nothing in the statement prevents it.

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Possibility Shortcut

If the statement does not prohibit it,
Possibility = True.

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Syllogism Master Rules

Rule 1

All + All

can create a new conclusion.

Example:

All A are B.
All B are C.

Conclusion:

All A are C.

True.

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Rule 2

Some + Some

No definite conclusion.

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Rule 3

No + All

Draw a Venn diagram.

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Syllogism Exam Strategy

1. Draw circles.

2. Check conclusions one by one.

3. Avoid assumptions.

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QUICK SYLLOGISM CHEAT SHEET

All A are B

Some A are B ✓
Some B are A ✓
All B are A ✗

No A are B

No B are A ✓
Some A are B ✗

Some A are B

Some B are A ✓

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2. STATEMENTS & CONCLUSIONS

What is a Conclusion?

Something that logically follows from the statement.

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Example

Statement:

The government increased road safety awareness.

Conclusion:

Road safety may improve.

Reasonable.

Follows.

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Conclusion:

All accidents will stop.

Too extreme.

Does not follow.

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Extreme Words Rule

Be careful when you see:

Always
Never
Only
Every
All
None

Usually incorrect unless explicitly stated.

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Example

Statement:

Many students use laptops.

Conclusion:

All students use laptops.

Wrong.

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Conclusion Test

Ask:

Is it 100% guaranteed?

If yes:

Follows.

If maybe:

Does not follow.

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Common Conclusion Traps

Trap 1: Generalization

Statement:

Some people exercise.

Conclusion:

Everyone exercises.

Wrong.

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Trap 2: Adding Information

Statement:

Cars are increasing.

Conclusion:

People prefer luxury cars.

Not given.

Wrong.

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3. STATEMENTS & ASSUMPTIONS

What is an Assumption?

A hidden belief behind a statement.

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Example

Statement:

Wear seat belts while driving.

Assumption:

Seat belts improve safety.

Without this belief, the statement loses meaning.

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Assumption Finding Method

Ask:

What must be true
for this statement to make sense?

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Example

Statement:

Buy this water purifier.

Assumption:

Water needs purification.

True.

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Example

Statement:

Study hard to clear TCS NQT.

Assumption:

Studying improves your chances.

True.

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Assumption Trap

Statement:

Use an umbrella in the rain.

Assumption:

Umbrella protects from rain.

Yes.

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Assumption:

Rain is dangerous.

Not necessary.

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4. DATA SUFFICIENCY

Very common in placement exams.

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Goal

Do not solve completely.

Determine whether the information is sufficient.

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Standard Options

A. Statement 1 alone is sufficient.

B. Statement 2 alone is sufficient.

C. Both together are sufficient.

D. Either statement alone is sufficient.

E. Data is not sufficient.

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Example

Question:

What is x?

Statement 1:

x + 2 = 5

Enough.

Answer:

x = 3

Statement 1 is sufficient.

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Example

Question:

What is x?

Statement 1:

x + y = 10

Not enough.

Statement 2:

y = 4

Together sufficient.

Answer:

Both statements are sufficient.

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Data Sufficiency Strategy

Check Statement 1.

Check Statement 2.

Check Both Together.

Never solve fully unless necessary.

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Common Trap

Students calculate everything.

Wrong approach.

Only verify sufficiency.

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5. OBJECTIVE REASONING

Questions based on logical decision-making.

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Example

All employees must submit ID.

Ravi is an employee.

Conclusion:

Ravi must submit ID.

Valid.

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Common Forms

Conditional Logic

Decision Making

Logical Inference

Rule Application

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Conditional Logic

If A → B

Meaning:

A leads to B.

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Example:

If it rains,
the road becomes wet.

Given:

It rains.

Conclusion:

The road becomes wet.

Valid.

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Common Trap

If Rain → Wet Road

Students conclude:

Wet Road → Rain

Wrong.

There may be another reason.

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6. INFERRED MEANING

Tests hidden or contextual meaning.

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Example

Sentence:

The company is tightening its belt.

Meaning:

Reducing expenses.

Not a literal belt.

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Common Placement Examples

Break the Ice

Start a conversation.

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Hit the Books

Study seriously.

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Once in a Blue Moon

Very rarely.

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Piece of Cake

Very easy.

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Under the Weather

Feeling sick.

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Inference Strategy

Ask:

Literal meaning?

Context meaning?

Choose the contextual meaning.

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LOGICAL REASONING MASTER CHECKLIST

When solving any logical reasoning question:

1. Read slowly.

2. Ignore real-world knowledge.

3. Use only given information.

4. Avoid extreme conclusions.

5. Check assumptions.

6. Draw diagrams if needed.

7. Verify before answering.

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2-MINUTE EXAM CHEAT SHEET

Syllogism

All A are B

Some A are B ✓
Some B are A ✓
All B are A ✗

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Conclusions

100% guaranteed?

YES → Follows
NO  → Does not follow

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Assumptions

Hidden belief behind the statement.

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Data Sufficiency

Check:

1 alone
2 alone
Both together

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Conditional Logic

A → B

A true ⇒ B true

B true ⇒ A is NOT necessarily true

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Inference

Meaning from context.

Not literal meaning.