UPSC Prelims 2017 · CSAT
Question 10: Logical Reasoning and Mental Ability
No supporters of ‘party X’, who knew Z and supported his campaign strategy, agreed for the alliance with ‘party Y’; but some of them had friends in ‘party Y’. With reference to the above information, consider the following statements :
- 1.Some supporters of ‘party X’ knew Z.
- 2.Some supporters of ‘party X’, who opposed Z’s campaign strategy, knew Z.
- 3.No supporters of ‘party X’ supported Z’s campaign strategy.
Which of the statements given above is/are not correct?
AnswerUPSC’s answer is (c).
Let G be the X supporters who knew Z and backed his strategy. Some of G have friends in Y, so G is not empty. Statement 1 therefore holds, and statement 3 is false because members of G supported the strategy. Statement 2 concerns X supporters who opposed the strategy; the information does not rule them out, so it is treated as acceptable. Only statement 3 is not correct.
- 1. G is not empty, so some X supporters did know Z.
- 2. Not contradicted: the information says nothing against X supporters who knew Z but opposed his strategy, so it is treated as acceptable.
- 3. Members of G supported Z's strategy, so it is wrong to say none did.
How you could have got this
- If you were sure statement 1 is correct, (a) and (d) go: each of them includes 1.
What you needed to know: G is not empty, so some X supporters did know Z.
- Then, if you were sure statement 2 is correct, (b) goes: it includes 2.
What you needed to know: Not contradicted: the information says nothing against X supporters who knew Z but opposed his strategy, so it is treated as acceptable.
Only (c) is left. You didn’t need statement 3.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Statement 1 is correct, so it cannot be the one that is wrong.
- (b) Statement 2 is not contradicted by the information, so it is not counted as wrong.
- (c) Correct: statement 3 denies that any X supporter backed Z's strategy, which contradicts the information.
- (d) Statements 1 and 2 are acceptable, so not all three are wrong.
Worth knowing: Statement 2 does not strictly follow from the information (it is only consistent with it); UPSC's key counts it as correct, which makes the question debatable.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2017, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.