If U = {a, b, c, d, e, f}, A = {a, b, d}, and B = {b, c, d}, what is (A ∪ B)'?
Answer and explanation
Correct answer: {e, f}
First form the union by listing every element that occurs in A or B: A ∪ B = {a, b, c, d}. The complement of this union contains the elements of U that are absent from it. In U, those remaining elements are e and f. Hence (A ∪ B)' = {e, f}. This also agrees with De Morgan’s law: (A ∪ B)' = A' ∩ B'.
Frequently asked questions
What is the correct answer to this question?
{e, f}
Why is this the correct answer?
First form the union by listing every element that occurs in A or B: A ∪ B = {a, b, c, d}. The complement of this union contains the elements of U that are absent from it. In U, those remaining elements are e and f. Hence (A ∪ B)' = {e, f}. This also agrees with De Morgan’s law: (A ∪ B)' = A' ∩ B'.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Complement of a Set and Its Properties.