If A = {1, 2, 3, 4, 5, 6}, B = {2, 3}, and C = {5, 6, 7}, what is A − (B ∪ C)?
Answer and explanation
Correct answer: {1, 4}
First calculate the union inside the parentheses: B ∪ C = {2, 3, 5, 6, 7}. Now A − (B ∪ C) means retain elements of A that are absent from this union. Removing 2, 3, 5, and 6 from A leaves {1, 4}. Although 7 belongs to the union, it is not in A and cannot appear in the difference. Thus option A is correct.
Frequently asked questions
What is the correct answer to this question?
{1, 4}
Why is this the correct answer?
First calculate the union inside the parentheses: B ∪ C = {2, 3, 5, 6, 7}. Now A − (B ∪ C) means retain elements of A that are absent from this union. Removing 2, 3, 5, and 6 from A leaves {1, 4}. Although 7 belongs to the union, it is not in A and cannot appear in the difference. Thus 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).
