Seven people, L, M, N, O, W, X and Y, are sitting in a row facing north (but not necessarily in the same order). Only L sits to the left of X. Only four people sit between L and N. Only M sits between O and W, and O is not an immediate neighbour of N. Who sits at the extreme right end of the row?

Seven boxes B, C, D, I, J, K and L are kept one over the other but not necessarily in the same order. Only I is kept above C. Only L is kept between C and J. Only K is kept below D. How many boxes are kept between B and I?

Seven people, M, N, O, P, Q, R, and S are sitting in a straight line, facing North. Only two people sit to the right of Q. Only two people sit between Q and M. N sits second to the right of M. P sits to the immediate right of R. O sits at one of the positions to the left of S. Who sits at the extreme left end of the line?