Read the following statement carefully and identify the conclusion that follows. Statement: Some cats are dogs.All dogs are animals. Conclusions: I. Some cats are animals. II. All cats are animals.
- (a)Only I follows
- (b)Only II follows
- (c)Both I and II follow
- (d)Neither I nor II follows
Answer
Why
Correct — A.
Rule: Some A are B + All B are C → Some A are C (but not All A are C).
Some cats are dogs, and every dog is an animal.
So the cats that are dogs are animals: Some cats are animals. I follows.
The statements say nothing about cats that are not dogs.
They may fall outside animals, so All cats are animals is not certain. II does not follow → option (a).
Why the others are wrong
- (b)Only II follows — All cats are animals needs every cat inside animals, but the statements place just some cats there. And Conclusion I does follow, so Only II fails twice.
- (c)Both I and II follow — Real-world knowledge says every cat is an animal, but the statements alone do not. A syllogism is judged on what is given, so II cannot join I.
- (d)Neither I nor II follows — Some cats are animals is forced. The cats that are dogs sit inside dogs, and dogs sit wholly inside animals, so Neither cannot be right.
Concept
A syllogism is decided by the statements alone. Draw dogs as a circle wholly inside animals, and cats as a circle that overlaps dogs.
The overlap lies inside animals, so some cats are animals. The rest of the cats circle can stretch outside animals, and no statement stops it. So all cats are animals is possible, but not definite.
General knowledge says every cat is an animal, which makes Conclusion II feel safe. The key still rejects it: a conclusion must follow from the statements, not from the world. This item does not print the rider about commonly known facts, but it is judged the same way.
Key facts
- Some A are B + All B are C gives Some A are C.
- The same two statements do not give All A are C.
- A some-statement reverses: Some cats are animals also means Some animals are cats.
Study next
Common traps
- Marking II true because every real cat is an animal
- Reading Some cats are dogs as All cats are dogs
Here SSC gives two statements and pairs a some-conclusion with an all-conclusion.
19 Sep 2024, 16:00, Reasoning Q.19 runs the same chain one link longer, Some shirts are pants, All pants are jackets, All jackets are trousers, and keys Only conclusion I: Some trousers are shirts.
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