Chapter 8 of 14

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SSC CGL General Intelligence & Reasoning★ Tier 1: 1–2 Q (2–4 marks) · Tier 2: 2–4 Q (6–12 marks)

Syllogism

1–2 questions in Tier 1 and 2–4 in Tier 2 — statements assumed true, conclusions to validate. The Venn-diagram method decides every case: draw the minimal diagram, test each conclusion against it, and remember that "some" never implies "all" and true statements can be absurd.

⏱ 18 min readModerate difficulty✓ Free · exam-pattern aligned

Timed practiceMCQs from this chapter with instant scoring

FlashcardsFormulas & traps on spaced repetition

SSC CGL PYQsSolved previous-year questions

By the end of this chapter you'll be able to…

1Draw the minimal Venn diagram for each of the four statement types (All, No, Some, Some-not) and know exactly what each does NOT imply
2Apply the certainty test — a conclusion follows only if it holds in every legal diagram — and the break test to kill non-forced conclusions
3Detect the 'either–or' case: complementary conclusion pairs on the same two terms where neither follows alone
4Handle possibility conclusions ('All A being B is a possibility') with the one-supporting-diagram test
5Chain multi-statement premises (3 statements, 3–4 conclusions) without losing track of which overlaps are forced versus optional

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Why this chapter matters in SSC CGL

Syllogism is pure logic with zero formulas — once the Venn-diagram discipline is in place, every question is a guaranteed 40–60 second score. SSC keeps it in both tiers because untrained candidates lose marks to real-world intuition ('pens can't be cows') and to the some/all asymmetry. Trained candidates treat it as free marks, and in Tier 2 at 3 marks per question with −1 negative, that reliability matters.

Before you start — revise these

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Analogy

Builds the habit of testing a rule against every option — the same discipline syllogism needs for testing conclusions against diagrams.

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Classification

Category membership reasoning — thinking in sets and subsets — is exactly what Venn circles formalise.

Syllogism — SSC CGL Reasoning

A syllogism gives you statements to treat as absolutely true — even "All cats are buildings" — and conclusions to test. The only legal question is: does the conclusion HAVE to be true in every diagram the statements allow? If you can draw even one valid diagram where the conclusion fails, it is not a valid conclusion. This chapter is the drawing discipline.

1. What SSC actually asks

Tier 1: 1–2 Q · Tier 2: 2–4 Q. Format: 2–3 statements, 2–4 conclusions, options like "only I follows / both follow / either I or II follows". Content is deliberately absurd (pens are cows) to punish real-world knowledge — logic only.

2. The four statement types and their diagrams

Statement	Minimal diagram	What it does NOT say
All A are B	A-circle inside B	NOT "All B are A"
No A is B	disjoint circles	— (this one is symmetric)
Some A are B	overlapping circles	NOT "Some A are not B"
Some A are not B	A partly outside B	NOT "Some A are B"

The golden asymmetries:

All A are B ⇒ "Some B are A" ✓ (valid conversion), but never "All B are A".
Some A are B ⇒ "Some B are A" ✓ (symmetric), but never "Some A are not B".
No A is B ⇒ "No B is A" ✓ and "Some A are not B" ✓ — the latter needs A to have at least one member, and SSC convention treats every named class as non-empty, so it follows.

3. The method: minimal diagram + break test

Draw the minimal diagram — the least-committed arrangement satisfying all statements (overlap circles only as much as forced).
Test each conclusion: must it hold in this diagram? If yes —
Try to break it: redraw the statements in an alternative legal way (expand a circle, separate an overlap). If any legal diagram kills the conclusion → it does not follow.
"Either–or" check (the step everyone forgets): if two conclusions individually fail but together they cover all possibilities for the same pair (e.g., "Some A are B" and "No A is B"), the answer is "either I or II follows." Trigger conditions: same two terms, complementary pair (some/none, all/some-not), and neither follows alone.

4. Possibility conclusions (Tier-2 flavour)

Conclusions phrased "Some A being B is a possibility" follow when at least one legal diagram allows it (the opposite of the usual test — possibility needs one supporting diagram, certainty needs all).

After "All A are B": "All B being A is a possibility" ✓ (circles could coincide).
After "Some A are B": "All A being B is a possibility" ✓.
After "No A is B": any A-B overlap possibility ✗ — definitively blocked.

5. Solved PYQ-style examples

Q1. All pens are cows. All cows are chairs. Conclusions: I. All pens are chairs. II. Some chairs are pens. Solution. Chain: pens ⊆ cows ⊆ chairs → I ✓. Chairs contain pens → II ✓. Both follow.

Q2. Some books are pins. All pins are rods. Conclusions: I. Some books are rods. II. Some rods are books. Solution. The book–pin overlap sits inside rods → some books are rods ✓, and conversion gives II ✓. Both follow.

Q3. All roses are flowers. Some flowers are red. Conclusion: Some roses are red. Solution. The red-flowers overlap may avoid the rose circle entirely — draw it that way, conclusion dies. Does not follow. (The classic middle-term trap: "some" of a superset never reaches a specific subset.)

Q4. No cup is a plate. Some plates are spoons. Conclusions: I. Some spoons are not cups. II. Some spoons are cups. Solution. Spoons overlapping plates are outside cups → I ✓ (those spoons are definitely not cups). II can be drawn either way → fails alone. Not complementary here since I follows. Only I follows.

Q5. Some A are B. No B is C. Conclusions: I. Some A are not C. II. Some A are C. Solution. The A∩B region is outside C → I ✓. II is possible but not forced → ✗. Only I follows.

Q6 (either–or). All keys are locks. Some locks are doors. Conclusions: I. Some keys are doors. II. No key is a door. Solution. I can be drawn true or false; II likewise — neither is forced. Same terms (keys, doors), complementary pair (some / none) → either I or II follows.

6. Exam protocol

Circles on paper for every question — mental Venn is how "some" becomes "all" under pressure.
Ignore real-world sense entirely; absurd content is deliberate.
Certainty test: must hold in every legal diagram. Possibility test: holds in at least one.
Before marking "none follows", run the either–or check on failed complementary pairs.
40–60 seconds per question; two statements = one diagram + one break attempt.

Key formulas & results

Everything to memorise for the exam hall, in one card. Screenshot this for revision.

Valid conversions

All A are B \Rightarrow Some B are A; Some A are B \Rightarrow Some B are A; No A is B \Rightarrow No B is A

The only three conversions that are always legal. 'All A are B' never converts to 'All B are A'.

Certainty test

Conclusion follows ⟺ true in EVERY legal diagram

One counter-diagram kills a conclusion. Always attempt the break before accepting.

Possibility test

Possibility follows ⟺ true in AT LEAST ONE legal diagram

The mirror image of the certainty test — only blocked when a statement definitively rules it out (e.g., 'No A is B' blocks all A–B overlap possibilities).

Either–or trigger

Same 2 terms + complementary pair + neither follows alone \Rightarrow either/or

Complementary pairs: (Some, No) and (All, Some-not). Both conditions must involve the same two terms in the same order of meaning.

SSC CGL test series

Ready to be tested on this?

Syllogism shows up in every SSC CGL paper — sit a timed one and find out where you actually stand.

1–2Qs in Tier 1

Highpriority

Full SSC CGL mocks, real clock
General Intelligence & Reasoning-only sectionals & chapter tests
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Traps SSC CGL sets — and how to dodge them

These are the exact option-traps and misreads that cost marks under negative marking.

WATCH OUT

✗ Converting 'All A are B' to 'All B are A' — assuming the container equals the contents.

✓ Draw it: A is a small circle inside B. B has room outside A. Only 'Some B are A' is forced.

WATCH OUT

✗ Reading 'Some A are B' as also implying 'Some A are not B'.

✓ 'Some' means 'at least one' — it is silent about the rest. All A could be B. The two statements are independent.

WATCH OUT

✗ Chaining 'some' through a middle term: All roses are flowers + Some flowers are red → Some roses are red.

✓ The 'some' of a superset need not touch a specific subset. Draw the red overlap away from roses — the conclusion dies, so it does not follow.

WATCH OUT

✗ Marking 'none follows' without running the either–or check.

✓ Whenever two conclusions on the same pair of terms individually fail, check if they are complementary (some/none or all/some-not). If yes, the answer is 'either I or II follows'.

WATCH OUT

✗ Using real-world knowledge — rejecting 'All cats are buildings' as false.

✓ Statements are assumed absolutely true, however absurd. The absurdity is deliberate, designed to punish knowledge and reward logic.

WATCH OUT

✗ Testing possibility conclusions with the certainty test (or vice versa).

✓ Read the conclusion's wording first. 'Is a possibility' needs one supporting diagram; a plain assertion needs all diagrams. Mixing the two flips the answer.

Exam-pattern practice

PYQ-style questions with full solutions. Work through them as a readiness check — mark yourself honestly and get your gap report at the end.

Readiness check

Are you exam-ready for Syllogism?

10 problems from this chapter. Try each one, reveal the worked solution, mark yourself honestly — get your gap report at the end.

10 questions~7 min

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

•Statements are absolutely true — ignore real-world sense; absurd content is deliberate
•Valid conversions: All A are B ⇒ Some B are A; Some A are B ⇒ Some B are A; No A is B ⇒ No B is A
•Never: All A are B ⇒ All B are A; never: Some A are B ⇒ Some A are not B
•Certainty test: must hold in EVERY legal diagram — one counter-diagram kills it
•Possibility test: needs just ONE legal diagram — blocked only by a definitive 'No' statement
•'Some' of a superset never reaches a specific subset (the rose–flower–red trap)
•Either–or trigger: same two terms + complementary pair (some/no or all/some-not) + neither follows alone
•Always draw circles on paper; mental Venn is how 'some' becomes 'all' under time pressure
•Budget 40–60 seconds per question: minimal diagram, then one break attempt per conclusion

SSC CGL question blueprint

How this topic is asked, tier by tier — so you can prep to the pattern.

Typical weightage: 16

Question style	Marks each	Typical count	What it tests
Tier 1 — two statements, two conclusions	2–4 (1–2 Q × 2 marks)
Tier 2 — three statements / possibility type	6–12 (2–4 Q × 3 marks)

Prep strategy

Master the four statement diagrams and three valid conversions first — one sitting, permanent payoff
Drill 20 questions of each type: basic chains, negative premises, either–or, possibility
Practise drawing three-statement diagrams incrementally without erasing
Timed sets of 10 questions in 8 minutes to lock the 40–60 second rhythm

Exam-hall strategy

Battle-tested tips from mentors and toppers for this topic under the sectional clock.

Draw circles for every question — even 'obvious' ones. The 10 seconds spent drawing prevents the some→all slip that costs 2–3 marks plus negative marking.
Test conclusions in order of ease: forced chains (All + All) first, then negatives, then possibilities.
When an option says 'none follows', treat it as a prompt to run the either–or check before marking it.
In Tier 2, expect three-statement sets — build the diagram incrementally, one statement at a time, and re-scan all three statements before testing conclusions.
If a question takes more than 90 seconds, mark for review and move on — syllogism sets later in the paper may be easier.

Beyond the exam

Where this skill shows up in the job you're competing for — and in life.

Contract and policy reading

Legal clauses are syllogisms: 'All employees in grade A get allowance X; no contractor is a grade-A employee.' Deciding what actually follows — and what only seems to — is the same certainty test.

Database queries and set logic

SQL joins and set operations (subset, intersection, disjoint) are Venn diagrams executed by a machine. Debugging why a query returns unexpected rows is a break test on your assumed diagram.

Spotting flawed arguments

Most rhetorical sleight-of-hand is an invalid conversion: 'All experts agree X, she agrees X, so she is an expert.' Syllogism training makes the illegal step visible instantly.

Where else this topic is tested

Prepare once, score in every exam that asks it.

SSC CHSL2–3 Q — same pattern, slightly easier statements

SSC MTS1–2 Q — two-statement basics

IBPS PO / Clerk4–5 Q — heavier on possibility and 'only a few' variants

RRB NTPC1–2 Q — direct two-statement type

📝 My notes

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Questions aspirants ask

Pulled from the Q&A community and mentor sessions.

Typically 1–2 questions in Tier 1 (2 marks each) and 2–4 in Tier 2 Paper 1 (3 marks each). Tier 2 versions more often use three statements or possibility-type conclusions.

For SSC CGL, Venn diagrams. The rule-based method (distribution of terms) is faster for experts but error-prone under pressure. Drawing the minimal diagram plus one break attempt is reliable and still fits inside 60 seconds with practice.

It means neither conclusion is individually forced, but between them they exhaust every possibility, so exactly one must be true. It only applies when both conclusions use the same two terms and form a complementary pair: some/none, or all/some-not.

Yes. SSC answer keys follow the convention that every named class has at least one member. That is why 'No A is B' supports 'Some A are not B' — because A is guaranteed to have members, all of whom are outside B.

The test flips. A normal conclusion must hold in every legal diagram; a possibility ('All A being B is a possibility') needs just one legal diagram where it holds. A possibility fails only when the statements definitively block it — usually a 'No X is Y' premise.