M, N, O, W, X and Y live on six different floors of the same building. The lowermost floor in the building is numbered 1, the floor above it is numbered 2 and so on till the topmost floor is numbered 6. O lives on floor numbered 4. Only two people live between O and N. Only X lives between O and M. W lives immediately below O. Who lives on floor numbered 2?

Seven boxes D, E, F, U, V, W and X are kept one over the other but not necessarily in the same order. No box is kept above X. Only two boxes are kept between W and V. Only U is kept below E. Only three boxes are kept between E and W. D is not kept immediately above V. How many boxes are kept between F and U?

In a certain building arrangement, the number of floors between Q4 and P9 is the same as the number of floors between S2 and which of the following?