If A = {x : x ∈ N, x ≤ 4} and B = {4, 3, 2, 1}, which statement is correct?
Answer and explanation
Correct answer: A = B
Using the standard school convention N = {1, 2, 3, ...}, the natural numbers not exceeding 4 are 1, 2, 3, and 4. Hence A = {1, 2, 3, 4}. Set B contains exactly these same elements, merely written in reverse order. The order of elements does not matter in a set, so A = B. Option B is false for this reason; option C is false because equal sets are not proper subsets of one another; and option D is false because B has four elements.
Frequently asked questions
What is the correct answer to this question?
A = B
Why is this the correct answer?
Using the standard school convention N = {1, 2, 3, ...}, the natural numbers not exceeding 4 are 1, 2, 3, and 4. Hence A = {1, 2, 3, 4}. Set B contains exactly these same elements, merely written in reverse order. The order of elements does not matter in a set, so A = B. Option B is false for this reason; option C is false because equal sets are not proper subsets of one another; and option D is false because B has four elements.
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.
