Directions (87-91) : Study the following information carefully and answer the questions given below.

Twelve persons sit on twelve seats arranged in a row but only some persons are known and all of them are facing towards the north direction. Y is the only neighbour of S. Three persons sit between S and O who sits immediately left of K. More than three persons sit between K and H. K sits 2nd to the left of P who sits exactly between K and U. The number of persons sit between P and B is multiple of 2. The prime number of persons sits between H and B.

How many persons sit to the left of B?

` tag. Let's draft the solution output cleanly. Two

The correct option is Two.

Step-by-Step Explanation and Derivation:

Let 12 seats be arranged in a single row facing North, numbered 1 to 12 from left to right.

1. Position of S and Y:

We are given that Y is the only neighbour of S. For a person in a single row to have only one neighbor, that person must sit at one of the extreme ends of the row.

• If S sits at the left end (Seat 1), then Y sits at Seat 2.
• If S sits at the right end (Seat 12), then Y sits at Seat 11.

2. Evaluating the Clues for Left End Case (S at Seat 1):

• Position of S and Y: S is at Seat 1, Y is at Seat 2.
• Position of O and K: Three persons sit between S and O, so O is at Seat 5 (since 1 + 3 + 1 = 5). Since O sits immediately to the left of K, K is at Seat 6.
• Position of P and U: K sits 2^nd to the left of P, placing P at Seat 8 (6 + 2 = 8). P sits exactly between K (Seat 6) and U, so U is at Seat 10.
• Position of H: More than 3 persons sit between K (Seat 6) and H. H must be to the right of K. Placing H at Seat 11 leaves 4 persons (Seats 7, 8, 9, 10) between K and H, which satisfies the condition (4 > 3).

3. Determining the Position of B:

• The number of persons sitting between P (Seat 8) and B must be a multiple of 2.
• The number of persons sitting between H (Seat 11) and B must be a prime number.
Placing B at Seat 3:
- Persons between P (Seat 8) and B (Seat 3) = 8 - 3 - 1 = 4 (which is a multiple of 2).
- Persons between H (Seat 11) and B (Seat 3) = 11 - 3 - 1 = 7 (which is a prime number).

4. Final Seating Arrangement (Seats 1 to 12):

Seat 1: S
Seat 2: Y
Seat 3: B
Seat 4: Unknown
Seat 5: O
Seat 6: K
Seat 7: Unknown
Seat 8: P
Seat 9: Unknown
Seat 10: U
Seat 11: H
Seat 12: Unknown

Conclusion:

B is at Seat 3. Therefore, exactly 2 persons (S at Seat 1 and Y at Seat 2) sit to the left of B.