1 votes 1 votes Given that X is a set of n elements. How many pairs of sets (A, B) exist such that A⊆B⊆S? a. 2n b. 2n+1 c. 3n Set Theory & Algebra discrete-mathematics set-theory&algebra + – Tuhin Dutta asked Jan 30, 2018 Tuhin Dutta 365 views answer comment Share Follow See all 4 Comments See all 4 4 Comments reply minal commented Jan 30, 2018 reply Follow Share is it 3^n , (a,b)= (0,0) or(0,1) or (1,1) here 0 is representing subset not present and 1 is subset present ... 0 votes 0 votes Tuhin Dutta commented Jan 30, 2018 reply Follow Share yes, the answer is correct but can you provide a bit more explanation, not able to get it fully. 0 votes 0 votes Avdhesh Singh Rana commented Jan 30, 2018 reply Follow Share https://math.stackexchange.com/questions/979894/number-of-pairs-of-subsets 1 votes 1 votes minal commented Jan 30, 2018 reply Follow Share as a and b are subset of s and a is subset of b , that means if a is present then b must bhi there (1,1), if b is not present then a must not be present (0,0) and if a is not present, may be b present ... (kind of finding anti asymmetric reln rt ) so here 3 choices 1 votes 1 votes Please log in or register to add a comment.