If U = {1, 2, ..., 12}, A = {1, 3, 5, 7, 9, 11}, and B = {2, 3, 5, 7, 11}, what is (A′ ∪ B′)′?
Answer and explanation
Correct answer: {3, 5, 7, 11}
All complements are taken with respect to the universal set U. By De Morgan’s law, (A′ ∪ B′)′ = A ∩ B. The intersection contains exactly those elements common to both A and B. Comparing the two sets, the common elements are 3, 5, 7, and 11. Therefore, the correct answer is option A: {3, 5, 7, 11}.
Frequently asked questions
What is the correct answer to this question?
{3, 5, 7, 11}
Why is this the correct answer?
All complements are taken with respect to the universal set U. By De Morgan’s law, (A′ ∪ B′)′ = A ∩ B. The intersection contains exactly those elements common to both A and B. Comparing the two sets, the common elements are 3, 5, 7, and 11. Therefore, the correct answer is option A: {3, 5, 7, 11}.
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.