Who lives on 4th

Solution

At least one person lives below P which means P lives either on 2nd or 3rd floor as S lives on the floors which is the 3 times of the floor number on which P lives. 2. Two persons live between S and V. Y lives on the topmost floor. Only one person lives between V and Q, who lives on odd numbered floor but below the sixth floor. So, S either lives on 6th or 9th floor. Also, V must be living below S as Q lives odd number floor below the 6th floor. Also, Q either lives on 5th or 1st floor. Case I: When P lives on 2nd floor: Case II: When P lives on 3rd floor but this case is invalid as Q lives on odd number floor: T lives above S. W lives three floors above the floor on which Q lives. 4. Three persons live between R and X. U lives immediately above T. Now, Q must be living on ground floor as W lives 3 floors above Q. Also, U either lives on 9th or 8th floor as T lives above S and immediately below U but as three persons live between R and X which means U must be living on 8th floor and either R or X lives on 9th floor. The final arrangement is as follows: