Ten people—J, K, L, M, N, O, P, Q, R, and S —live in a building with five floors and two flats (Flat 1 and Flat 2) on each floor. The floors are numbered from 1 to 5 (1 being the lowermost floor and 5 being the topmost floor).

Note I: Each floor has two flats viz., Flat-1 and Flat-2, where Flat 1 is to the west of Flat 2.

Note II: Flat 1 of floor 2 is immediately above Flat 1 of floor 1 and immediately below Flat 1 of floor 3 and so on. Similarly Flat 2 of floor 2 is immediately above Flat 2 of floor 1 and immediately below Flat 2 of floor 3 and so on.

Note III: The area of each flat is equal.

Note IV: Only two persons live on each floor and only one person lives in each flat.

L lives on an even -numbered floor in Flat -1. P lives in Flat -2 of the topmost floor. N lives west of Q. N lives on a floor immediately below the L’s floor. K and R live on the same named flat. K and L lives in a different named flat. Only one floor is between K and O. K lives below O. S lives to the west of P. M lives immediately below O, but not in the same named flat. One floor between J’s floor and L’s floor.

Who lives in Flat 1 on the topmost floor?

To find out who lives in Flat 1 on the topmost floor, we can step-by-step place the ten individuals (J, K, L, M, N, O, P, Q, R, and S) into the grid of 5 floors (1 to 5) and 2 flats (Flat 1 and Flat 2) on each floor.

Let's analyze the given clues:
1. S lives to the west of P: Since P lives in Flat-2 of the topmost floor (floor 5), S must live in Flat-1 of floor 5 (since Flat-1 is to the west of Flat-2 on the same floor). Therefore, S lives in Flat 1 of floor 5, and P lives in Flat 2 of floor 5.
2. L lives on an even-numbered floor in Flat-1: The even-numbered floors are 2 and 4. Since Flat 1 of floor 5 is occupied by S, we look at where L can be. L is in Flat-1 on either floor 2 or floor 4.
3. N lives west of Q: This means N and Q are on the same floor, with N in Flat 1 and Q in Flat 2.
4. N lives on a floor immediately below L's floor: Since L is on an even floor (2 or 4), the floor immediately below L's floor must be an odd floor (1 or 3). Since N lives in Flat 1 and Q in Flat 2 on this floor, floor 1 or floor 3 is occupied by N and Q.
5. K and L live in a different named flat: Since L lives in Flat-1, K must live in Flat-2.
6. K and R live in the same named flat: Since K is in Flat-2, R must also live in Flat-2.
7. Only one floor is between K and O, and K lives below O: O is on a higher floor than K, with exactly one floor between them.
8. M lives immediately below O, but not in the same named flat: This means M is on the floor immediately below O.
9. One floor between J's floor and L's floor: This relates J's floor to L's floor.

From the first clue, we immediately determine that S lives in Flat 1 of floor 5 and P lives in Flat 2 of floor 5. Thus, the person who lives in Flat 1 on the topmost floor (floor 5) is S.