Find the number of subsets X of `{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}` such that X contains at least two elements and that no two elements of X differ by 1.

Let A={1, 2, 3, 4, 5, 6, 7, 8, 9, 10}. Then the number of subsets of A containing exactly two elements is

Find the unit digit of the number of non empty subsets S of {1,2,3,4,5,6,7,8,9,10,11,12} such that no two consecutive integers belong to S and if S contains k elements it contains no elements less than k

Let A = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} . Then the number of subsets of A containing two or three elements is:

Let A={1, 2, 3, 4, 5, 6, 7, 8, 9, 10}. Then the number of subsets of A containing two or three elements is

If X={1,2,3,{4,5},6,{7,8,9,10} then {4,5} sub X

If A = {1, 2, 3, 4, 5, 6} then how many subsets of A contain the elements 2, 3 and 5?

If A={1,2,3,4,5,6} , then the number of subsets of A which contain atleast two elements is

Number of non-empty subsets {1,2,3,4,5,6,7,8} having exactly k elements and do not contain the element k for some k = 1,2"….."8 is

Number of non-empty subsets {1,2,3,4,5,6,7,8} having exactly k elements and do not contain the element k for some k = 1,2"….."8 is