If A = ∅, how many members are there in P(P(P(A)))?
Answer and explanation
Correct answer: 4
Start with A = ∅, which has 0 elements. Its power set is P(A) = {∅}, so |P(A)| = 1. Taking the power set again gives a set with 2¹ = 2 elements, so |P(P(A))| = 2. Taking the power set a third time gives 2² = 4 elements. Therefore, |P(P(P(A)))| = 4, making option B correct.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
Start with A = ∅, which has 0 elements. Its power set is P(A) = {∅}, so |P(A)| = 1. Taking the power set again gives a set with 2¹ = 2 elements, so |P(P(A))| = 2. Taking the power set a third time gives 2² = 4 elements. Therefore, |P(P(P(A)))| = 4, making option B correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Power Set and Subsets.