Sets

If A = {1, 2, 3, 4} and B = {3, 4, 5, 6}, what is A ∪ B?

If U = {1, 2, 3, ..., 10} is the universal set and A = {2, 4, 6, 8, 10}, what is A'?

If A = {x : x is a multiple of 3 less than 20} and B = {x : x is a multiple of 4 less than 20}, what is A ∩ B?

Given sets A and B with n(A) = 7, n(B) = 5 and n(A ∪ B) = 9, find n(A ∩ B).

If A = {1, 2, 3} and B = {a, b, c}, what is the number of elements in A × B?

If A ⊆ B and B ⊆ C, which of the following is always true?

If A = {x ∈ ℕ : x ≤ 10} and B = {x ∈ ℕ : x is even and x ≤ 10}, find (A - B) ∪ (B - A).

If n(U) = 30, n(A) = 15, n(B) = 20, and n(A ∩ B) = 10, find n(A' ∩ B').

If A and B are subsets of universal set U such that A ∪ B = U and A ∩ B = ∅, then which of the following is true?

For sets A, B, and C, which of the following is always true?