Study the following information carefully and answer the questions given below-

Ten persons P to Y live in 10 storey building but not necessarily in the same order. The bottommost floor is numbered as 1 and so on till the topmost floor is numbered as 10.

V lives on prime numbered floor but below 4th floor. S lives below V but not on the ground floor. There are as many persons live above S as below P. More than three persons live between P and Y who lives above X. One person lives between T and Y. W lives just below R. U does not live below Q.

The numbers of persons live between R and Y is half than the numbers of persons live below _____________.

To find the correct answer, we can reconstruct the step-by-step floor arrangement from the given clues. The building has 10 floors, numbered 1 (bottommost) to 10 (topmost).

Step 1: Determine the positions of V and S.
- V lives on a prime-numbered floor below the 4th floor. The prime floors below 4 are 2 and 3.
- S lives below V, but not on the ground floor (floor 1).
- If V were on floor 2, S would have to be on floor 1, which contradicts the rule. Therefore, V must live on floor 3, and S must live on floor 2.

Step 2: Find the position of P.
- There are as many persons living above S as below P.
- Since S is on floor 2, the number of floors above S is:
$10\; -\; 2\; =\; 8$
- Therefore, there must be 8 floors below P, which means P lives on floor 9.

Step 3: Determine the positions of Y and X.
- More than 3 persons live between P (floor 9) and Y, and Y lives above X.
- For more than 3 persons to live between P and Y, there must be at least 4 floors between them. Thus, Y can be on floor 4 or lower.
- If Y were on floor 1, he could not live above X. Since floors 2 and 3 are occupied by S and V, Y must live on floor 4.
- Since Y lives above X, and the only available floor below Y is floor 1, X must live on floor 1.

Step 4: Find the position of T.
- One person lives between T and Y (floor 4). This means T must be on either floor 6 or floor 2. Since floor 2 is occupied by S, T must live on floor 6.

Step 5: Determine the positions of R and W.
- W lives just below R. This requires two consecutive vacant floors.
- The currently vacant floors are 5, 7, 8, and 10.
- The only consecutive vacant floors are 8 and 7. Thus, R must live on floor 8, and W must live on floor 7.

Step 6: Place Q and U.
- The remaining vacant floors are 5 and 10.
- Since U does not live below Q (meaning U lives above Q), U must live on floor 10, and Q must live on floor 5.

Final Floor Arrangement:
10: U
9: P
8: R
7: W
6: T
5: Q
4: Y
3: V
2: S
1: X

Answering the question:
- The number of persons living between R (floor 8) and Y (floor 4) is 3 (namely W, T, and Q on floors 7, 6, and 5).
- The question states: "The number of persons live between R and Y is half than the number of persons live below [Blank]".
- Since 3 is half of 6, we need to find the person below whom exactly 6 persons live.
- The person who has 6 persons living below them (on floors 1 to 6) must live on floor 7.
- W lives on floor 7. Therefore, the blank must be filled with W.