UPSC Prelims 2013 · CSAT
Question 10: Logical Reasoning and Mental Ability
Four friends, A, B, C and D distribute some money among themselves in such a manner that A gets one less than B, C gets 5 more than D, D gets 3 more than B. Who gets the smallest amount ?
AnswerUPSC’s answer is (a).
Let B's share be x. A gets one less than B: x - 1. D gets 3 more than B: x + 3. C gets 5 more than D: x + 8. Ordering the shares gives x - 1 < x < x + 3 < x + 8, so A gets the smallest amount. A quick check with x = 10 gives A 9, B 10, D 13 and C 18. In ranking puzzles, express every person in terms of one variable and compare.
Why each option is right or wrong
- (a) Right. A = x - 1 is below B, D and C.
- (b) Wrong. B = x is above A.
- (c) Wrong. C = x + 8 is the largest.
- (d) Wrong. D = x + 3 is above both B and A.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2013, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.