UPSC Prelims 2019·CSAT·Logical Reasoning·Deductive Logic

Consider the following Statements and Conclusions: Statements: 1. Some rats are cats. 2. Some cats are dogs. 3. No dog is a cow. Conclusions: I. No cow is a cat. II. No dog is a rat. III. Some cats are rats. Which of the above conclusions is/are drawn from the statements?

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  1. AI, II and III
  2. BOnly I and II
  3. COnly IIICorrect
  4. DOnly II and III

Explanation

The problem requires us to determine which conclusions logically follow from the given statements. Let's analyze each conclusion: Statements: 1. Some rats are cats. 2. Some cats are dogs. 3. No dog is a cow. Conclusion I: No cow is a cat. From statement 3, we know that dogs and cows are completely separate (No dog is a cow). From statement 2, we know that some cats are dogs. This means there's an overlap between cats and dogs. However, we cannot conclude anything definitive about the relationship between *all* cats and cows. While the cats that are dogs are not cows, there could be other cats that are not dogs, and these cats *could* be cows. The statements do not provide enough information to establish that no cow is a cat. Therefore, this conclusion is not necessarily true. Conclusion II: No dog is a rat. From statement 1, some rats are cats. From statement 2, some cats are dogs. We have an overlap between rats and cats, and an overlap between cats and dogs. However, these "some" relationships do not guarantee that there is no overlap between rats and dogs. It's possible that the "some cats" that are rats are also among the "some cats" that are dogs, leading to some rats being dogs. Conversely, it's also possible they are entirely separate groups. Since we cannot definitively conclude "No dog is a rat," this conclusion is not necessarily true. Conclusion III: Some cats are rats. Statement 1 directly says: "Some rats are cats." If "Some rats are cats," it logically and necessarily follows that "Some cats are rats." This is a direct and valid immediate inference. Based on the analysis, only Conclusion III is drawn from the statements. The final answer is C) Only III
Logical Reasoning: Consider the following Statements and Conclusions: Statements: 1. Some rats are cats. 2. Some cats are dogs. 3. No dog i

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