Algebra
posted by Mary .
Given A = {0, 3, 5, 8, 9}, B = {1, 2, 3, 6, 7, 8}, C = {0, 1, 4, 6, 7}, and the universal set U = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, what is the complement of set B?
Is the answer A?
Choices
A. 0, 4, 5, 9
B. 1, 2, 4, 6, 7
C. 2, 3, 5, 8, 9
D. 1, 2, 3, 6, 7

Complement of set B is a set that contains ALL the members of the universal set LESS the members of set B.
In other words, some properties of the complement of set B are:
1. B'∪B = U
i.e. two to sets combined contains all elements of the universal set.
2. B'∩B = ∅, i.e. the two sets have no common elements.
3. B' = UB
i.e. B' is formed by taking elements from U all elements contained in B.
Out of the 4 possible choices, there is only one set that satisfies property (2). Confirm the two other properties once you have made your choice.