UPSC Prelims 1998 · General Studies
Question 140: Logical Reasoning and Mental Ability
A, B, C, D, E and F, not necessarily in that order, are sitting on six chairs regularly placed around a round table. It is observed that A is between D and F, C is opposite D, and D and E are not on neighbouring chairs. Which one of the following pairs must be sitting on neighbouring chairs?
AnswerThe answer is (b).
Number the chairs 1 to 6 round the table and put D at chair 1. A is between D and F, so A is at chair 2 and F at chair 3 (or the mirror image). C is opposite D, at chair 4. B and E take chairs 5 and 6. Chair 6 is next to D, and D and E are not neighbours, so E is at chair 5 and B at chair 6. E is then next to C.
Why each option is right or wrong
- (a) A and B sit at chairs 2 and 6, so they are not neighbours.
- (b) Right: C and E must be neighbours.
- (c) B and F are on opposite sides of the table.
- (d) A and C are separated by one chair, so they are not neighbours.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1998, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.