If A = {∅, {∅}}, what is n(A), the number of elements in A?
Answer and explanation
Correct answer: 2
The outer set A has two elements: the empty set ∅ and the singleton set {∅}. These are different objects. The symbol ∅ denotes a set with no elements, whereas {∅} denotes a set whose one element is the empty set. Since the two outer elements are distinct, n(A) = 2.
Frequently asked questions
What is the correct answer to this question?
2
Why is this the correct answer?
The outer set A has two elements: the empty set ∅ and the singleton set {∅}. These are different objects. The symbol ∅ denotes a set with no elements, whereas {∅} denotes a set whose one element is the empty set. Since the two outer elements are distinct, n(A) = 2.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.