Let A be a set containing n elements. If the number of elements in the set, `B={(x,y,z):xepsilon A, yepsilon A, zepsilon A and x,y,z` are not all distict) is equal to 280, the n= (A) 8 (B) 10 (C) 20 (D) none of these

Let A be a finite set containing n elements, then the number of relations on A is

Let X be any non-empty set containing n elements, then the number of relations on X is

Let A and B infinite sets containing m and n elements respectively. The number of relations that can be defined from A to B is

Let X be a set containing n elements. Two subsets A and B of X are chosen at random, the probability that AuuB=X is

S is a set containing n elements. A subset AS of S is selected . The set S is reconstructed by replacing the elements of A.A subset B of S is now selected. If the numer of ways of selecting subsets A and B of S such that AcapB=phi is 81, then n= (A) 3 (B) 4 (C) 5 (D) none of these

Let A be a set of n (>=3) distinct elements. The number of triplets (x, y, z) of the A elements in which at least two coordinates is equal to

The number of elements in the set {(a,b) : a^(2) + b^(2) = 50, a, b in Z} where Z is the set of all integers, is

Let X be a set containing n elements. If two subsets A and B of X are picked at random, the probability that A and B have the same number of elements is

.Let X be a set containing n elements. If two subsets A and B of X are picked at random, the probability that A and B have the same number of elements is

The number of elements in the set {(a,b):2a^(2)+3b^(2)=35,a,b,inZ} , where Z is set of all integers is