Five people A, B, C, D and E are seated about a round table. Every chair is spaced equidistant from adjacent chairs. (i) C is seated next to A (ii) A is seated two seats from D (iii) B is not seated next to A On the basis of above information, which of the following must be true ? 1. D is seated next to B 2. E is seated next to A 3. D and C are separated by two seats Select the correct answer using the code given below :
- (a) 1 only
- (b) 1 and 2 only ✓ UPSC's answer
- (c) 3 only
- (d) Neither 1 nor 2 nor 3
Why the answer is (b)
• Number the five seats 1 to 5 round the table and put A at seat 1; A's neighbours are seats 2 and 5.
• 'A is two seats from D' puts D at seat 3 or seat 4 (the non-adjacent seats).
• C must take one neighbour seat of A (2 or 5), and B cannot sit next to A, so B takes the remaining non-neighbour seat (4 if D is at 3; 3 if D is at 4).
• In every case B sits next to D (statement 1 true) and E takes A's other neighbour seat (statement 2 true).
• D and C are sometimes adjacent and sometimes separated, so statement 3 need not be true.
• Hence 1 and 2 only, option (b).
Why the other options are wrong
- (a) 1 only
- Statement 2 (E is seated next to A) is also necessarily true, so '1 only' is incomplete.
- (c) 3 only
- Statement 3 is not necessarily true, and statements 1 and 2 are true, so '3 only' is incorrect.
- (d) Neither 1 nor 2 nor 3
- Statements 1 and 2 are necessarily true, so 'Neither' is incorrect.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2016, held on 7 August 2016. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.