MTS Multi Tasking Staff: General Intelligence & Reasoning — Syllogism (2026)

Syllogism — Logical Reasoning Guide

Key Rules:

  • All A are B + All B are C → All A are C (valid)
  • Some A are B + All B are C → Some A are C (valid)
  • All A are B + Some B are C → Some A are C (INVALID — cannot conclude)
  • No A is B + All B are C → No A is C (valid)

Venn Diagram Method: Draw all possible Venn diagram configurations and check if conclusion holds in ALL of them.

⚡ Rule: If a conclusion follows in ALL possible Venn diagrams, it is definitely true. If it fails in even one, it is uncertain or false.

Practice MCQs — Syllogism

Q1. All cats are dogs. All dogs are animals. Conclusion: All cats are animals?

  • A) True
  • B) False
  • C) Uncertain
  • D) Partially true
Answer: A) True — By transitivity: All cats→dogs→animals.

Q2. Some pens are books. All books are papers. Conclusion: Some pens are papers?

  • A) True
  • B) False
  • C) Uncertain
  • D) Cannot say
Answer: A) True — Some pens are books (which are papers) → Some pens are papers.

Q3. No bird is a fish. All fish are mammals. Conclusion: No bird is a mammal?

  • A) True
  • B) False
  • C) Uncertain
  • D) Partially true
Answer: B) False — Fish may be mammals but birds are not fish — birds could still be mammals from other paths.

Q4. All A are B. No B is C. Conclusion: No A is C?

  • A) True
  • B) False
  • C) Cannot determine
  • D) None follows
Answer: A) True — All A→B and No B→C → No A can be C.

Q5. Some students are teachers. Some teachers are doctors. Does: Some students are doctors?

  • A) True
  • B) False
  • C) Uncertain
  • D) None follows
Answer: C) Uncertain — 'Some' doesn't chain directly → uncertain.

Q6. All fruits are sweet. Some sweets are salty. Conclusion: Some fruits are salty?

  • A) True
  • B) False
  • C) Uncertain
  • D) Cannot say
Answer: B) False — Some sweets are salty doesn't mean the salty ones are fruits → uncertain.

Q7. All M are N. All N are O. All O are P. Conclusion: All M are P?

  • A) True
  • B) False
  • C) Uncertain
  • D) Partially true
Answer: A) True — Transitive chain: M→N→O→P.

Q8. No table is chair. Some chairs are beds. Conclusion: Some beds are not tables?

  • A) True
  • B) False
  • C) Cannot determine
  • D) None follows
Answer: A) True — Since some chairs are beds and no chairs are tables, those beds (that are chairs) are not tables.

Q9. All politicians are honest. Raju is a politician. Conclusion: Raju is honest?

  • A) True
  • B) False
  • C) Uncertain
  • D) None follows
Answer: A) True — Universal application.

Q10. Some A are B. All B are C. No C is D. Some A are not D?

  • A) True
  • B) False
  • C) Cannot say
  • D) Partially true
Answer: A) True — Some A are B(⊂C⊂not-D) → those some A are not D.