· R lives on the floor immediately below the one on which M lives.
· There is one floor between the one on which R and S live.
Also,
· K's flat is towards the east of M's flat.
we get, (here, S's and R's flat is not fixed)
Case I:
Case II:
Case III:
Now,
· T's and N's flat are on the same floor, which is not the top floor.
Thus,
Case III becomes invalid.
Case I:
|  | Flat 1 | Flat 2 | 
| 4 | M | K | 
| 3 | R |  | 
| 2 | T/N | N/T | 
| 1 | S/ | /S | 
Case II:
|  | Flat 1 | Flat 2 | 
| 4 | S/ | /S | 
| 3 | M | K | 
| 2 | R |  | 
| 1 | T/N | N/T | 
Now,
· P and R do not live on same floor and, P lives on a floor below T's floor.
Thus, case II is eliminated.
We get,
|  | Flat 1 | Flat 2 | 
| 4 | M | K | 
| 3 | R |  | 
| 2 | T/N | N/T | 
| 1 | S/P | P/S | 
Here,
· N lives on the flat immediately above S's flat.
And,
· R's flat is not immediately above T's flat.
So, we get,
Case I(a):
Case I(b):
Now,
· The floor on which three persons live is the third floor.
· R doesn't share the flat with any other person.
so, we get,
Case I(a):
|  | Flat 1 | Flat 2 | 
| 4 | M | K | 
| 3 | R | U, O | 
| 2 | N | T | 
| 1 | S | P | 
Case I(b):
|  | Flat 1 | Flat 2 | 
| 4 | M | K | 
| 3 | U, O | R | 
| 2 | T | N | 
| 1 | P | S | 
Since,
· U's flat is not immediately below M's flat.
So, case I(b) is eliminated and we get the final arrangement as follows:
|  | Flat 1 | Flat 2 | 
| 4 | M | K | 
| 3 | R | U, O | 
| 2 | N | T | 
| 1 | S | P | 
 
S lives on the bottommost floor.