Master Syllogism from Zero

Syllogism involves two or more statements (premises) from which you need to determine which conclusion(s) logically follow. Key Rules: 1. ALL A are B → Every A is inside B 2. NO A is B → A and B have no overlap 3. SOME A are B → At least one A is B (partial overlap) 4. SOME A are NOT B → At least one A is not B Venn Diagram approach is the most reliable method for TCS NQT.

Key Formulas

ALL + ALL = ALL

All A are B + All B are C → All A are C

Definite conclusion possible

ALL + NO = NO

All A are B + No B is C → No A is C

Definite conclusion possible

SOME + ALL = SOME

Some A are B + All B are C → Some A are C

Definite conclusion possible

SOME + NO = SOME NOT

Some A are B + No B is C → Some A are not C

Definite conclusion possible

⚡ Shortcut Tricks

Always draw Venn diagrams — it's the safest method for TCS NQT.

Remember: SOME means 'at least one' — it could be all or few.

When conclusions say 'SOME', they are easier to prove true.

When ALL + ALL → ALL is always a definite conclusion.

If both premises have SOME, no definite conclusion is possible.

Complementary pairs: if conclusion 1 says 'All A are B' and conclusion 2 says 'Some A are not B', one of them must be true — answer is 'Either 1 or 2'.

TCS NQT frequently tests: All+No=No, Some+All=Some, All+All=All combinations.

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