If all the persons from the top of the building live in ascending order of their experience then, the floor of how many persons remains unchanged?

Q lives on an even number floor. R, who lives on any floor below floor number 4, lives three floors away from Q and doesn’t have experience of 12 years. That means, in case (2) Q lives on floor number 6, in case (1) Q lives on floor number 4. Neither Q nor R lives on the adjacent floor of X, who lives four floors away from the one whose experience is 7 years. The number of persons living between Q and X is the same as the number of persons living below P, whose experience is 17 years. That means, in case (2) X lives on floor number 8, case (1) is not valid. Based on the above given information we have: Case (1) is not valid as the number of persons living between Q and X is the same as the number of persons living below P, whose experience is 17 years. Again, we have: V lives three floors above the one whose experience is 21 years. That means, in case (2) V lives on floor number 9, in case (2a) V lives on floor number 4. The number of persons living between V and the one whose experience is 26 years is one more than the number of persons living between the one whose experience is 12 years and W. The experience of X is neither 26 nor 14 years. W lives on any floor above the one whose experience is 12 years but not adjacent to Q’s floor. W doesn’t live on the topmost floor. That means, in case (2) the one whose experience is 12 years lives on floor number 1, case (2a) is not valid. Based on the above given information we have: Case (2a) is not valid as W lives on any floor above the one whose experience is 12 years but not adjacent to Q’s floor and W doesn’t live on the topmost floor. Again, we have: The one whose experience is 14 years lives two floors away from S. U has less experience than T. The number of persons living between S and Q is the same as between S and the one whose experience is 9 years. Since, persons whose experiences are in common multiple are not living on the adjacent floor. This, the experience of S is 13 years. Based on the above given information we have