Seating arrangement for RRB NTPC: rows, circles and the left–right rule

Seating questions give a handful of clues about where five to eight people sit, in a row or around a table, and then ask two or three questions about the final arrangement. They take longer than most reasoning questions, often a minute or more for the first question in a set. The good news is that once the arrangement is drawn, the follow-up questions take seconds.

Almost every error in this topic comes from one of two slips: applying "right" and "left" the wrong way, or placing people from a vague clue before the fixed ones. A set order of work removes both.

The left–right rule

To check the circle rule, imagine sitting at the bottom of the table facing the centre. Your right hand points towards the right-hand side of the page, and moving there along the circle is anticlockwise.

Words you need to read precisely

• Immediate right / left: the very next seat on that side.
• Second to the right: skip one seat, then take the next.
• Between: in a row, somewhere between two people; "immediately between" means next to both.
• Opposite: in a circle of an even number of people, directly across (n ÷ 2 seats away).
• Neighbours: the two people on either side.

A method

1. Draw the row or circle and number the seats. For a circle, number clockwise.
2. Place people from fixed clues first: "C is in the middle", "A is at the left end", "P sits opposite S".
3. Use relative clues next: "B is to the immediate right of C".
4. Use negative clues last ("E is not at an end") to choose between the seats that are left.
5. If two cases remain, draw both side by side and let the next clue remove one.
6. Check every clue against the final arrangement before answering.

In a circle, the first person can go in any seat, because only the positions relative to each other matter. Put them in seat 1 and build around them.

Worked puzzle 1: a row facing north

Five people, A, B, C, D and E, sit in a row facing north.

• C is in the middle.
• A is at the left end.
• B is to the immediate right of C.
• E is not at an end.

Solving: number the seats 1–5 from left to right. A = 1 and C = 3. Facing north, right is the page's right, so B = 4. Seats 2 and 5 remain, and E is not at an end, so E = 2 and D = 5.

Arrangement: A, E, C, B, D.

• Who is at the right end? D.
• Who sits between A and C? E.

Worked puzzle 2: a circle facing the centre

Six people, P, Q, R, S, T and U, sit around a circular table facing the centre.

• P sits opposite S.
• Q is to the immediate right of P.
• R is to the immediate left of S.
• T does not sit next to P.

Solving: number the seats 1–6 clockwise and put P in seat 1. S is opposite, in seat 4. Right is anticlockwise, so Q is in seat 6. Left is clockwise, so R is in seat 5. Seats 2 and 3 remain. P's neighbours are seats 2 and 6, so T cannot be in seat 2. So T = 3 and U = 2.

Arrangement (clockwise from seat 1): P, U, T, S, R, Q.

• Who sits opposite Q? T (seats 6 and 3).
• Who sits between T and R? S.
• Who is to the immediate right of U? P (one seat anticlockwise from U).

Worked puzzle 3: a row facing south

Six people, F, G, H, I, J and K, sit in a row facing south.

• G sits at the extreme left end.
• I is third to the right of G.
• K sits to the immediate left of I.
• H is not at an end.
• J sits to the immediate right of H.

Solving: draw six seats across the page, numbered 1–6 from your left, with the people facing you. Their right is your left.

• G is at their left end, which is your right: seat 6.
• Third to G's right means three seats towards your left: seat 3 is I.
• K is to I's immediate left, one seat towards your right: seat 4.
• F, H and J take seats 1, 2 and 5. H is not at an end, so H is 2 or 5.
• J is to H's immediate right, one seat towards your left. If H = 5, J would need seat 4, which is K's. So H = 2, J = 1 and F = 5.

Arrangement (seats 1 to 6 on the page): J, H, I, K, F, G.

• Who is at the extreme right end? J (their right is your left).
• How many people sit between I and G? Two (K and F).
• Who is to the immediate left of H? I.

Common mistakes

• Applying the row rule to a circle. Facing the centre, right is anticlockwise.
• Forgetting to flip left and right for a row facing south.
• Starting with negative clues. They only help once the fixed and relative clues have narrowed the choice.
• Reading "second to the right" as "immediate right".
• Not re-checking every clue at the end. One missed clue can mean two possible arrangements.

Practice set

Set A. Five friends, J, K, L, M and N, sit in a row facing north.

• L is at the right end.
• J is second from the left.
• M sits between J and N, next to both.
• K is not at the right end.

1. Who is at the left end?
2. Who sits in the middle?
3. Who is to the immediate left of L?
4. How many people sit between K and N?

Set B. Six people, A, B, C, D, E and F, sit around a circular table facing the centre.

• A sits opposite D.
• B is second to the left of A.
• C sits to the immediate left of D.
• E does not sit next to B.

1. Who sits opposite F?
2. Who is to the immediate right of A?
3. Who are D's two neighbours?
4. Who is second to the right of D?

Set A answers:

1. K. The arrangement is K, J, M, N, L. J = 2 and L = 5; M must be next to J and to N, so M = 3 and N = 4, leaving K = 1.
2. M.
3. N.
4. Two (J and M).

Set B answers:

1. C. Seats clockwise from A: A, F, B, D, C, E. Put A in seat 1 and D in seat 4. Left is clockwise, so B is in seat 3 and C in seat 5. B's neighbours are seats 2 and 4, so E cannot be in seat 2; E = 6 and F = 2. F (2) is opposite C (5).
2. E. One seat anticlockwise from A (seat 1) is seat 6.
3. B and C.
4. F. Two seats anticlockwise from D (seat 4) is seat 2.

What to do next

• Draw the R arrow on every circle diagram for your next 15 puzzles.
• Solve five rows facing south in a row, until the flip is automatic.
• Time yourself: aim to have the arrangement drawn within 90 seconds, then answer each follow-up in 10.
• Revise order and ranking, then move on to puzzles, which use the same clue order.