Seating Arrangement

Seating problems give a set of people with constraints (who sits next to whom, who faces north/south, etc.) and ask their positions.

Linear arrangement (single row): people sit in a row, all facing one direction (say north).

• "X is to the left of Y" — X is to your right if you're facing them, i.e. their left from their own perspective.
• "X sits 3rd from the left" — position 3 counting from left.
• Position from left + position from right = total + 1.

Two rows facing each other: row 1 faces south, row 2 faces north. "X is opposite Y" means same column.

Circular arrangement:

• All facing centre OR all facing outward — opposite "left/right" conventions!
• Facing centre: your right neighbour is the one on your right hand side, which is clockwise from you on the circle.
• Facing outward: your right is anti-clockwise.

Step-by-step approach:

1. Read all conditions and list them as bullets.
2. Find a "fixed" clue — an absolute position ("A sits at the head of the table", "B is third from the left").
3. Place that person first.
4. Apply other clues one by one, eliminating impossible arrangements.
5. If multiple arrangements satisfy all constraints, the answer for "definitely follows" is in the common part.

"Immediate left of" = position one slot to the left. "Left of" (without "immediate") usually means somewhere to the left.

"Neighbour": adjacent (left or right).

"Between": strictly between two others — implies they are non-adjacent if more than one person sits between.

Common error: confusing facing direction in circular setups. Always re-read whether the group faces the centre or outward before placing anyone.

Example 1 — Linear, single row:
Six friends A, B, C, D, E, F sit in a row facing north. C is to the immediate left of A. B sits at the right end. E is to the immediate left of D. F is between A and D.
Solve:

• B at right end (position 6).
• "C immediate left of A" → CA together.
• "E immediate left of D" → ED together.
• F between A and D → A_F_D or D_F_A.
  Combine: arrangement attempts → C A F E D B works: position 1=C, 2=A, 3=F, 4=E, 5=D, 6=B. Check: F between A(2) and D(5)? F is at 3, between 2 and 5 ✓. E immediate left of D? E at 4, D at 5 ✓. C left of A? C at 1, A at 2 ✓. B right end ✓.

Example 2 — Circular, facing centre:
Five friends sit around a round table facing the centre. P is to the right of Q. R is opposite P. S is between P and Q.
Solve: Circle with 5 — but "opposite" usually only makes clean sense for even numbers. Let's say 6 people; or here R is "across" P. Place Q. P is right of Q (clockwise neighbour). S between P and Q — but P is already neighbouring Q, so "between" doesn't fit unless we have S separating them. Treat "between" loosely as one of: P–S–Q. So order clockwise: Q–P–…, with S between them in a 5-circle — actually we need diagram and 5 chairs. (RRB usually gives 8 or 6 — practise with those.)

Example 3 — Five people in a row:
A, B, C, D, E. A is at one end. B is third from the right. E is between A and C.
Solve: A is at left or right end. B is at position 3 (in 5-row, 3rd from right = 3rd from left). Place A at position 1, B at 3. E between A and C → E at 2, C must be to E's right, position 4 or 5. D fills the rest. Order: A E B C D or A E B D C — only the position of C and D differ. If a question asks "who is at position 4?", both arrangements give different answers → it's "cannot be determined" unless more clues exist.

Tactic: use a fixed-position clue first, then connectivity clues, then exclusion clues. If multiple valid arrangements remain, "Cannot be determined" is often a valid option.