If A = {2, 3, 4, 5} and B = {4, 5, 6, 7}, what is (A − B) ∪ (B − A)?
Answer and explanation
Correct answer: {2, 3, 6, 7}
First calculate the two differences separately. A − B contains the elements in A that are absent from B, so A − B = {2, 3}. Similarly, B − A contains the elements in B that are absent from A, so B − A = {6, 7}. Taking their union gives {2, 3} ∪ {6, 7} = {2, 3, 6, 7}. The common elements 4 and 5 are excluded, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
{2, 3, 6, 7}
Why is this the correct answer?
First calculate the two differences separately. A − B contains the elements in A that are absent from B, so A − B = {2, 3}. Similarly, B − A contains the elements in B that are absent from A, so B − A = {6, 7}. Taking their union gives {2, 3} ∪ {6, 7} = {2, 3, 6, 7}. The common elements 4 and 5 are excluded, so option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
