Let A = {p, q, r,s}, B = {p, q, r} and C = {q, s}. Find all sets X such that : `X sub B` and `X sub C`

Let A = {p, q, r,s}, B = {p, q, r} and C = {q, s}. Find all sets X such that : X sub A and X cancel (sub) B .

Let A = {1, 2, 3, 4}, B = {1, 2, 3} and C = {2, 4}. Find all sets X satisfying pair of conditions : X sub A, X sub B and X sub C .

Let A = {1, 2, 3, 4}, B = {1, 2, 3} and C = {2, 4}. Find all sets X satisfying pair of conditions : X sub B and X cancel (sub) C .

Let A = {1, 2, 3, 4}, B = {1, 2, 3} and C = {2, 4}. Find all sets X satisfying pair of conditions : X sub B, X ne B and X cancel (sub) C .

If A = { a, b,c}, B = {p,q}, find BxxA .

If A xx B = {(p, q), (p, r), (m, q),(m, r)} , find A and B.

Add: p ( p – q), q ( q – r) and r ( r – p)

Consider the following relations: R = {(x, y) | x, y are real numbers and x = wy for some rational number w}; S={(m/n , p/q)"m , n , p and q are integers such that n ,q"!="0 and q m = p n"} . Then (1) neither R nor S is an equivalence relation (2) S is an equivalence relation but R is not an equivalence relation (3) R and S both are equivalence relations (4) R is an equivalence relation but S is not an equivalence relation