Eight people are sitting in two parallel rows, containing four people each, in…
2025
Eight people are sitting in two parallel rows, containing four people each, in such a way that there is equal distance between adjacent persons.
In row 1 – R, S, T and U are seated and all of them are facing south. In row 2 – L, M, N and O are seated and all of them are facing north.
Thus, each person faces another person from the other row. T sits third to the left of U. The person facing T is an immediate neighbour of O. L sits second to the left of O. The person facing M is an immediate neighbour of U. R sits to the immediate right of S. Which of the following represents both people sitting at extreme ends of the line?
Answer: D. L, T — Concept: In a parallel-row (double-row) arrangement the two rows face each other, so a direction word does not carry the same meaning in both rows: whichever…
- A.
U, M
- B.
S, M
- C.
R, T
- D.
L, T
Show answer & explanation
Correct answer: D
Concept: In a parallel-row (double-row) arrangement the two rows face each other, so a direction word does not carry the same meaning in both rows: whichever way "left" runs for a person in one row, it runs the opposite way for a person in the row facing it. The dependable method is to fix one drawing frame, restate every left/right clue inside that single frame, and start from the clue that admits the fewest placements. Because the rows face each other, the person in seat n of one row always faces the person in seat n of the other row.
Application:
Set the frame. Draw four seats numbered 1 to 4 from left to right for both rows, so that seat n of Row 1 faces seat n of Row 2. Row 1 (R, S, T, U) faces south, so for a Row 1 person "left" runs toward seat 4 and "right" runs toward seat 1. Row 2 (L, M, N, O) faces north, so for a Row 2 person "left" runs toward seat 1 and "right" toward seat 4.
Apply "T sits third to the left of U" in Row 1. Left for this row means moving toward seat 4, so T's seat is three greater than U's seat. In a four-seat row the only fit is U at seat 1 and T at seat 4.
Apply "R sits to the immediate right of S" in Row 1. Right for this row means one seat toward seat 1, so R sits one seat before S. Only seats 2 and 3 remain, which gives R at seat 2 and S at seat 3.
Apply "L sits second to the left of O" in Row 2. Left for this row means moving toward seat 1, so L's seat is two less than O's seat. That leaves two candidates: O at seat 3 with L at seat 1, or O at seat 4 with L at seat 2.
Apply "the person facing T is an immediate neighbour of O". T is at seat 4, so the Row 2 person in seat 4 must sit next to O, and seat 4 has only one neighbour, seat 3. Hence O is at seat 3, which forces L to seat 1, and M and N are left for seats 2 and 4.
Apply "the person facing M is an immediate neighbour of U". U is at seat 1. If M were at seat 4, the person facing M would be T at seat 4, whose only neighbour is S at seat 3, and that is not U. So M is at seat 2, faced by R at seat 2, and R does sit next to U. N therefore takes seat 4.
Read off the two end seats of each row. Row 1 has U at seat 1 and T at seat 4; Row 2 has L at seat 1 and N at seat 4. The people at the extreme ends are therefore U, T, L and N, so the pair whose two names both belong to that set is L and T.
Seat | Row 1 (facing south) | Row 2 (facing north) |
|---|---|---|
1 | U | L |
2 | R | M |
3 | S | O |
4 | T | N |
Cross-check:
For a south-facing person, T at seat 4 is three seats to the left of U at seat 1, and R at seat 2 is immediately to the right of S at seat 3.
For a north-facing person, L at seat 1 is two seats to the left of O at seat 3; N at seat 4 faces T and sits next to O; R at seat 2 faces M and sits next to U. All five clues hold.
Mirroring the whole diagram, that is numbering the seats the other way round, changes every seat number but leaves the same four people on the end seats, so the result does not depend on which way the rows were drawn.