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RAS question

Statement: 'No cat is a dog. All dogs are animals.' Conclusion I: No cat is an animal. Conclusion II: Some animals are not cats. Which conclusion(s) follow(s)?

Correct answer: (B) Only Conclusion II follows.

From the statements "No cat is a dog" and "All dogs are animals", only Conclusion II follows: some animals are not cats.

  1. (A)

    Only Conclusion I follows

  2. (B)

    Only Conclusion II follows

  3. (C)

    Both I and II follow

  4. (D)

    Neither I nor II follows

Explanation

This is a deductive reasoning question: the source explains that a conclusion must follow with logical certainty from the given premises, and a valid conclusion cannot go beyond the information supplied. The premises say two things only: no cat belongs to the class of dogs, and every dog belongs to the class of animals. Therefore, the dogs are a definite set of animals, and because no dog is a cat, those animals are certainly not cats. That proves Conclusion II. Conclusion I overreaches: the statements separate cats from dogs, but they do not separate cats from the wider class of animals.

Why the other options are wrong

  • (A) Conclusion I does not follow because the premises never say that cats are outside the class of animals; they only say cats are outside the class of dogs.
  • (C) Both conclusions cannot follow because Conclusion II is forced by the dog-animal relation, while Conclusion I adds a wider cat-animal exclusion not given in the premises.
  • (D) It is wrong to reject both conclusions because dogs are animals and no dog is a cat, so at least some animals, namely dogs, are not cats.

Concept

This tests categorical syllogism and Venn-diagram style class reasoning, where the task is to identify what necessarily follows from quantified statements. It recurs in RAS because reasoning questions often reward strict inference and penalise assumptions beyond the premises.

Source

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