Hello I need help with this problem

LetSbe a set withnelements.

(a)How many ordered pairs are there inS × S?

(b) How many relations are there onS(subsets ofS × S) ?

LetA, B, Cbe 3 sets. Suppose|A|=|B|=|C|= 100,|A \ B|= 70,

|A \ C|= 50,|B \ C|= 45 and|A [B [ C|= 175. How many elements are there inA \ B \ C?

\ means intersection and [ means union

Thank you