UPSC Prelims 2019 · CSAT
Question 13: Logical Reasoning and Mental Ability
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 ?
AnswerUPSC’s answer is (c).
Statement 1 says some rats are cats. A 'some' statement can be reversed, so some cats are rats, which is conclusion III. Conclusion I does not follow: cats that are not dogs may still be cows. Conclusion II does not follow either: the cats that are dogs need not be the cats that are rats, so a rat may or may not be a dog. Only III is drawn.
- I. Cats outside the dog group could be cows.
- II. No link between the rat-cats and the dog-cats is given.
- III. Some rats are cats reverses to some cats are rats.
Why each option is right or wrong
- (a) Wrong: I and II do not follow.
- (b) Wrong: neither I nor II follows.
- (c) Right: III is the reverse of statement 1.
- (d) Wrong: II does not follow, since the dog-cats may not be the rat-cats.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2019, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.