Syllogism Questions for RRB NTPC

Types of Statements

Every syllogism question uses one of four types of statements. Each type has a specific logical meaning. You must treat these like math rules, not English sentences. Real-world knowledge is irrelevant here.

• All A are B — Universal Positive (UP): Every single member of A is inside B
• No A is B — Universal Negative (UN): Zero overlap between A and B
• Some A are B — Particular Positive (PP): At least one member of A is also in B
• Some A are not B — Particular Negative (PN): At least one member of A is NOT in B

The Conversion Rules

When you reverse (convert) a statement, the result must still be logically valid. Conversion helps you match statements when the middle term is at different positions in two premises.

• All A are B converts to Some B are A (UP becomes PP)
• No A is B converts to No B is A (UN stays UN)
• Some A are B converts to Some B are A (PP stays PP)
• Some A are not B has NO valid conversion — never convert PN type

The Syllogism Combination Rules (3 Golden Rules)

When two premises share a middle term (like A-B and B-C), you can combine them to derive a conclusion about A and C. The three rules below tell you what conclusion is possible. If none of these rules apply, no definite conclusion exists.

• Rule 1: UP + UP = UP. All A are B + All B are C = All A are C
• Rule 2: UP + UN = UN. All A are B + No B is C = No A is C (and converts to No C is A)
• Rule 3: UP + PP = PP. All A are B + Some B are C = Some A are C (or Some C are A)
• Rule 4: UN + PP = PN. No A is B + Some B are C = Some C are not A (note direction carefully)
• If both premises are Particular (PP, PN) or both are Negative, NO conclusion is possible
• If one premise is Particular, conclusion must be Particular; if one is Negative, conclusion must be Negative

Either-Or Conclusion (Complementary Pair)

Sometimes neither conclusion alone follows, but the exam offers an Either-Or option. This is valid only when the two conclusions are complementary, meaning one is the positive and the other is the negative form of the exact same subject-predicate pair. Think of it as a forced choice when one must be true.

• Complementary pair: Some A are B (PP) and Some A are not B (PN) about the same A and B
• Also: All A are B (UP) and Some A are not B (PN) can form a complementary pair
• Either-Or is valid ONLY when neither conclusion independently follows from the statements
• If even one conclusion independently follows, Either-Or option is NOT the answer

Venn Diagram Method (Quick Visual Check)

If rule-based approach feels uncertain, draw quick circles. All A are B means circle A is completely inside circle B. No A is B means two separate non-touching circles. Some A are B means two overlapping circles. This is your backup method — use it to verify tricky questions in 30 seconds.

• All A are B: small circle A drawn inside big circle B
• No A is B: two circles with no overlap at all
• Some A are B: two circles with a shaded overlapping region
• Some A are not B: circle A partially sticks out of circle B
• A conclusion is valid only if it holds true in ALL possible Venn diagrams, not just one

• Using real-world knowledge: Students write All dogs are animals, so All animals are dogs is true. Wrong! Logical conversion of All A are B gives only Some B are A, never All B are A.
• Forgetting to align the middle term: Before applying combination rules, make sure the shared term appears as subject in one statement and predicate in the other. If not, first convert one statement.
• Applying Either-Or even when one conclusion already follows: Either-Or is a last resort. If Conclusion 1 follows on its own, the answer is Conclusion 1 follows, not Either-Or.
• Converting Some A are not B (PN type): PN has no valid conversion. Many students try to flip it and land on a wrong answer.
• Concluding from two particular or two negative statements: No definite conclusion is ever possible when both premises are particular (Some type) or both are negative (No type). Students often guess incorrectly in such cases.

• AUSNPPN rule table mnemonic: think UP UP UP, UP UN UN, UP PP PP, UN PP PN — chant it like a multiplication table until it sticks
• Conversion reminder — ALL SHRINKS, NO STAYS, SOME STAYS, PN DIES: All converts down to Some, No stays No, Some stays Some, Some Not cannot be converted
• Venn diagram visual anchor: All = baby inside mama (A inside B), No = two strangers (no touch), Some = two friends hugging (overlap), Some Not = one friend half-leaving the hug
• Either-Or trigger phrase: Neither alone? Try the pair! — only use Either-Or when both conclusions fail individually and they form a PP+PN pair on the same terms

• RRB NTPC typically gives 2-statement syllogisms with 2 conclusions and asks Follow, Does not follow, or Either-Or. Rarely 3 statements — but practice 3-statement chains too for newer paper patterns.
• Expected difficulty is easy to medium. A student who memorizes the 4 combination rules can solve each question in under 45 seconds, saving time for harder topics.
• Watch out for negative conclusions: No A is C is often the correct answer but students skip it because it sounds too harsh. Trust the rules.
• In recent RRB NTPC shifts (2019-2024), Either-Or questions appear at least once per set. Practice spotting complementary pairs quickly — it is a free mark if you know the rule.
• When pressed for time, use Venn diagrams only as a fallback. Rule-based approach is faster. Practice both so you can switch methods if you get stuck mid-paper.