Direction: Study the following information carefully and answer the given…
2020
Direction: Study the following information carefully and answer the given questions.
Eight persons i.e. A, B, C, D, P, Q, R and S are sitting around two inscribed square tables in such a way that four persons are seated at the four corners of the inner square and four at the four corners of the outer square. Persons sitting at the inner square and the outer square face each other.
C faces the one who sits 2nd to the right of S. Q is neither an immediate neighbour of S nor of C. D faces R and is an immediate neighbour of Q. A sits immediate left of R. B faces P. B and C are not immediate neighbours. Neither P nor A faces outside.
Four of the following five are alike in a certain way and so form a group. Find the one who does not belong to that group.
- A.
B
- B.
D
- C.
S
- D.
Q
- E.
C
Show answer & explanation
Correct answer: E
Concept
In a two-concentric-square seating puzzle, every person at the inner square faces the person directly across at the outer square; inner-square members face outward and outer-square members face inward toward the centre. So a person who does not face outside is an outer-square member. In a 4-corner square each person has exactly two immediate neighbours (the two adjacent corners) and one diagonally opposite person; "not an immediate neighbour" forces the diagonally opposite position. An odd-one-out group asks which item lacks the property shared by the other four.
Application: deduce the two squares
Neither P nor A faces outside, so P and A sit at the outer square.
A sits immediate left of R, so R is also at the outer square as a neighbour of A.
D faces R: since R is outer, the person facing R across the gap is at the inner square, so D is inner. D is an immediate neighbour of Q, so Q is inner too.
B faces P: since P is outer, B sits at the inner square.
So far Inner = {B, D, Q} and Outer = {A, P, R}. The remaining persons C and S fill one inner and one outer seat.
Test C inner and S outer: then both B and Q would have to sit opposite C, but a square has only one opposite corner, which is a contradiction; so this case is impossible.
Therefore C is outer and S is inner. Inner = {B, D, Q, S}; Outer = {A, P, R, C}.
Cross-check
C faces the one 2nd to the right of S: C (outer) faces the inner person diagonally opposite S, namely Q, which is consistent.
Q is opposite S on the inner square, so Q is not S's immediate neighbour; and Q (inner) and C (outer) are on different squares, so Q is not C's neighbour either.
B and C lie on different squares, so they are never immediate neighbours. All clues are satisfied, so the arrangement is unique.
Result: among the five names B, D, Q, S and C, the four B, D, Q and S all sit at the inner square, while C is the only one seated at the outer square. The shared property of the group is being an inner-square member, so C does not belong to the group.