How many cartons are kept between T and S?

Carefully read the information given and answer the questions asked. Eight cartons R, S, T, U, V, W X and Y are kept in a stack from bottom to top. Each carton is given a carton number, which is marked as 1, 2, 3, and so on from top to bottom. V is marked as a prime numbered carton. Number of cartons that are above V is more than the number of cartons that are below it. X and S are consecutive cartons below
V. No carton is there between S and U. Carton number of U is marked as double of the carton number of R. One of the cartons is kept between Y and T. W is not the first carton from the top in the stack and Y is not the sixth carton from the bottom.