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SSC CGL Syllogism

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This page covers SSC CGL Syllogism with complete concept notes, 46 graded practice MCQs, key points and exam-specific tips. Free to study.

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Concept Notes

Syllogism— Rules & Concept

Core ConceptRead this first — the foundation of the topic

SYLLOGISM — COMPLETE GUIDE FOR SSC CGL ─────────────────────────────────────

CORE CONCEPT ─────────────────────────────────────

Syllogism is a logic-based topic where you are given two or more statements and you must find which conclusions MUST be true based on those statements. You do NOT use your general knowledge. You only use what the statements tell you. Even if a conclusion seems true in real life, it is WRONG unless the statements prove it. ─────────────────────────────────────

KEY RULES / PROPERTIES ─────────────────────────────────────

There are 4 types of statements you will see: • Type A — Universal Positive: 'All A are B'

• Type E — Universal Negative: 'No A is B' • Type I — Particular Positive: 'Some A are B'

• Type O — Particular Negative: 'Some A are not B' Distribution Rule (very important):

A term is 'distributed' when the statement talks about ALL members of that group. — In 'All A are B': A is distributed, B is NOT

— In 'No A is B': Both A and B are distributed — In 'Some A are B': Neither A nor B is distributed

— In 'Some A are not B': Only B is distributed ─────────────────────────────────────

Formula BlockMemorise — at least one formula appears in every paper

(The Golden Combination Rules)

─────────────────────────────────────

These are the standard valid conclusion patterns. Memorise them:

1. All + All = All
(All A are B) + (All B are C) → All A are C
2. All + No = No
(All A are B) + (No B is C) → No A is C
3. Some + All = Some
(Some A are B) + (All B are C) → Some A are C
4. Some + No = Some Not
(Some A are B) + (No B is C) → Some A are not C
5. No + All = Some Not (Reversed)
(No A is B) + (All B are C) → Some C are not A
6. All + Some = No Definite Conclusion
(All A are B) + (Some B are C) → NO valid conclusion

EXTRA RULE: If both statements are Particular (Some + Some), NO conclusion is possible.

─────────────────────────────────────

Exam PatternsWhat examiners ask — read before attempting PYQs
Direct

'Which conclusion follows?' — choose from 4 options 2

Either-Or

When neither conclusion alone follows but together they cover all possibilities, the answer is 'Either I or II follows' Either-Or Trick: Use this ONLY when both conclusions are complementary (one positive + one negative about the same subject and predicate) AND individually neither follows. ─────────────────────────────────────

ShortcutsUse these to save 30–60 seconds per question
TRICK 2 — Complementary Pair Formula

For Either-Or to apply: Conclusion 1 + Conclusion 2 must be an I-O pair (Some A are C + Some A are not C) with the SAME subject and predicate. No other pair qualifies

TRICK 3 — Middle Term Check

For any two statements to give a conclusion, the MIDDLE TERM (the common term between both statements) must be distributed at least ONCE. If the middle term is NOT distributed in either statement, write NO CONCLUSION immediately. ─────────────────────────────────────

Worked ExampleSolve this step-by-step before moving on
1
Step 1

Identify the pattern — All + All = All

2
Step 2

Apply formula → All cats are animals. ✓ (Conclusion I follows)

3
Step 3

If All cats are animals, then reversing a universal positive gives 'Some animals are cats' (this is the converse of an A-type = I-type). ✓ (Conclusion II also follows) Answer: Both Conclusion I and II follow. ───────────────────────────────────── WORKED EXAMPLE 2 ───────────────────────────────────── Statements: 1. Some pens are books. 2. No book is a pencil. Conclusions: I. Some pens are not pencils. II. No pen is a pencil.

1
Step 1

Pattern = Some + No = Some Not

2
Step 2

Apply formula → Some pens are not pencils. ✓ (Conclusion I follows)

3
Step 3

'No pen is a pencil' would need All+No pattern. We only have Some+No, so this is too strong. ✗ (Conclusion II does NOT follow) Answer: Only Conclusion I follows. ───────────────────────────────────── #1 MOST COMMON TRAP ───────────────────────────────────── Students assume that if 'All A are B' is given, then 'All B are A' must also be true. THIS IS WRONG. The correct reverse of 'All A are B' is only 'Some B are A'. Reversing an All statement to another All statement is the biggest mistake in syllogism and directly costs marks in SSC CGL every year.

Key Points to Remember

  • Syllogism uses ONLY the given statements — never use real-world knowledge to decide conclusions.
  • Four statement types: A (All), E (No), I (Some), O (Some...not) — memorise these labels.
  • FORMULA: All + All = All conclusion is valid (e.g., All A are B + All B are C → All A are C).
  • FORMULA: Some + No = Some Not conclusion (e.g., Some A are B + No B is C → Some A are not C).
  • FORMULA: All + Some = NO definite conclusion — this combination gives nothing valid.
  • If BOTH statements are particular (Some + Some), NO conclusion can be drawn — ever.
  • Converse Rule: 'All A are B' converts to 'Some B are A' only, NOT 'All B are A'.
  • Either-Or applies ONLY when conclusions form a complementary I-O pair with the same subject and predicate and neither conclusion alone follows.
  • Middle Term must be distributed at least once in the two statements, otherwise no conclusion is possible.
  • Possibility questions: A possibility is TRUE unless a statement explicitly and completely blocks that overlap.

Exam-Specific Tips

  • The valid conversions are: A-type (All) converts to I-type (Some); E-type (No) converts to E-type (No); I-type (Some) converts to I-type (Some); O-type (Some not) has NO valid conversion.
  • In syllogism, 'All A are B' means B is NOT distributed — only A is distributed in an A-type statement.
  • In 'No A is B' (E-type), BOTH the subject (A) and predicate (B) are distributed — it is the only statement type where both terms are distributed.
  • The combination No + All gives the conclusion 'Some C are not A' (reversed Some Not) — this is a frequently tested pattern in SSC CGL.
  • Either-Or conclusion is valid ONLY when: (i) neither conclusion alone follows, AND (ii) the two conclusions are a complementary pair covering all logical possibilities.
  • Some + All = Some (valid conclusion) — for example, Some A are B + All B are C → Some A are C is a directly tested formula.
  • If the middle term is not distributed in at least one of the two premises, the syllogism is invalid and no conclusion follows — this is called the 'Fallacy of Undistributed Middle'.
Practice MCQs

Syllogism — Practice Questions

46graded MCQs · easy to hard · full solution & trap analysis · showing 20 of 46

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Practice 1easy

Statements: 1. All teachers are educated. 2. Some educated people are doctors. Conclusion: Some doctors are teachers. Which of the following is true about this conclusion?

Practice 2easy

Statements: 1. Some students are athletes. 2. All athletes are disciplined. Conclusion: Either some students are disciplined, or no students are disciplined. Which of the following is true?

Practice 3easy

Statements: 1. No criminals are honest. 2. All dishonest people are criminals. Conclusion: All dishonest people are criminals. Which of the following is true?

Practice 4easy

Statements: 1. All fruits are healthy. 2. All apples are fruits. Conclusion: All apples are healthy. Which of the following is true?

Practice 5easy

Statements: 1. All teachers are educated. 2. Some educated people are doctors. Conclusion: Some doctors are teachers. Which of the following is true?

Practice 6easy

Statements: 1. All teachers are educated. 2. Some educated people are doctors. Conclusion: Some doctors are teachers. Is the conclusion valid?

Practice 7easy

Statements: 1. Some athletes are disciplined. 2. All disciplined people are successful. Conclusion: Some athletes are successful. Is the conclusion valid?

Practice 8easy

Statements: 1. No politicians are saints. 2. All saints are honest. Conclusion: Some politicians are not honest. Is the conclusion valid?

Practice 9easy

Statements: 1. No reptiles are mammals. 2. All snakes are reptiles. Conclusion: No snakes are mammals. Is the conclusion valid?

Practice 10easy

Statements: 1. Some athletes are tall. 2. All tall people are strong. Conclusion: Either all athletes are strong, or no athletes are strong. Which of the following is correct?

Practice 11easy

Statements: 1. No reptiles are mammals. 2. All snakes are reptiles. Conclusion: No snakes are mammals. Is this conclusion valid?

Practice 12easy

Statements: 1. Some athletes are vegetarians. 2. All vegetarians are health-conscious. Conclusion: Some athletes are health-conscious. Is the conclusion valid?

Practice 13easy

Statements: 1. All doctors are professionals. 2. No professionals are unemployed. Conclusion: Either all doctors are employed OR some doctors are unemployed. Which statement is correct?

Practice 14easy

Statements: 1. No reptiles are mammals. 2. All snakes are reptiles. Conclusion: No snakes are mammals. Is the conclusion valid?

Practice 15easy

Statements: 1. All flowers are plants. 2. All plants need water. Conclusion: All flowers need water. Which statement best describes this conclusion?

Practice 16easy

Statements: 1. All flowers are plants. 2. All plants need water. Conclusion: All flowers need water. Which of the following is true?

Practice 17easy

Statements: 1. All teachers are educated. 2. Some educated people are doctors. Conclusion: Some teachers are doctors. Is the conclusion valid?

Practice 18easy

Statements: 1. No plants are animals. 2. All trees are plants. Conclusion: No trees are animals. Which of the following is true?

Practice 19medium

Statements: 1. All philosophers are critical thinkers. 2. Some critical thinkers are not writers. Conclusion: Which of the following must be true? (A) All philosophers are writers. (B) Some philosophers are not writers. (C) No philosophers are writers. (D) Either some philosophers are writers or some philosophers are not writers.

Practice 20medium

Statements: 1. All philosophers are critical thinkers. 2. Some critical thinkers are not scientists. Conclusion: Which of the following must be true? (A) All philosophers are scientists. (B) Some philosophers are not scientists. (C) No philosophers are scientists. (D) Either all philosophers are scientists or some philosophers are not scientists.

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60-Second Revision — Syllogism

  • Remember: NEVER reverse 'All A are B' into 'All B are A' — the correct reverse is only 'Some B are A'.
  • Formula: All+All=All | All+No=No | Some+All=Some | Some+No=Some Not — memorise all four before entering the exam hall.
  • Trap: Some+Some and All+Some both give NO valid conclusion — do not be tricked by attractive wrong options.
  • Either-Or Rule: Use it ONLY for complementary I-O pairs (Some A are C + Some A are not C) when neither alone follows.
  • Possibility questions: The answer is TRUE unless a statement explicitly blocks the overlap completely — when in doubt, the possibility exists.
  • Middle Term Check: Before solving, check that the common term between both statements appears distributed at least once — if not, write no conclusion and move on.
  • Converse Chart to recall: A→I, E→E, I→I, O→No conversion — this saves 30 seconds per question.
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