If A = {∅}, how many elements does P(A) have?
Answer and explanation
Correct answer: 2
Although A contains the empty set, A itself is not empty. The set A = {∅} has exactly one element: the empty set. A set with one element has 2^1 = 2 subsets. They are ∅ and {∅}. Therefore, P(A) = {∅, {∅}} and contains two elements. Confusing ∅ with {∅} would incorrectly lead to one, so option B is correct.
Frequently asked questions
What is the correct answer to this question?
2
Why is this the correct answer?
Although A contains the empty set, A itself is not empty. The set A = {∅} has exactly one element: the empty set. A set with one element has 2^1 = 2 subsets. They are ∅ and {∅}. Therefore, P(A) = {∅, {∅}} and contains two elements. Confusing ∅ with {∅} would incorrectly lead to one, so option B is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.