If U = {1, 2, 3} and A = ∅, what is A′?
Answer and explanation
Correct answer: {1, 2, 3}
The complement A′ contains all elements of the universal set U that are not in A. Since A is the empty set, it contains no elements, so none of the elements of U are removed. Therefore A′ = U − ∅ = U = {1, 2, 3}. Option A would be the set A itself, while options B and C omit elements that must remain in the complement. Thus option D is correct.
Frequently asked questions
What is the correct answer to this question?
{1, 2, 3}
Why is this the correct answer?
The complement A′ contains all elements of the universal set U that are not in A. Since A is the empty set, it contains no elements, so none of the elements of U are removed. Therefore A′ = U − ∅ = U = {1, 2, 3}. Option A would be the set A itself, while options B and C omit elements that must remain in the complement. Thus option D is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.
