List of top Quantitative Aptitude Questions on Sets

Out of the three thousand people living in a gated community,three hundred people have taken sim card from Company X and 1200 have taken sim card from Company Y.If 100 have taken sim cards from both X andY,how many have not taken any of the two?
If U = { 1, 2, 3, 4, 5, 6, 7, 8 } is the universal set, A = { 2, 3, 6, 7 }, B = { 3, 4, 5, 6 }, and C = { 5, 6, 7, 8 }, then n[̅A ∩ (C - B)] + n[̅A ∩ (B ∨ C)] = k, where ̅A is the complement of set A. The value of k is:
For the nonempty sets \( A \) and \( B \), which of the following is NOT true? \( \overline{A} \) is the complement of A