If A = {1, 3, 5, 7, 9}, B = {3, 6, 9}, and C = {1, 2, 3, 4}, what is (A ∪ B) \ C?
Answer and explanation
Correct answer: {5, 6, 7, 9}
First form the union A ∪ B by listing every distinct element from A and B: A ∪ B = {1, 3, 5, 6, 7, 9}. The difference (A ∪ B) \ C removes every element that occurs in C. Since C = {1, 2, 3, 4}, the elements 1 and 3 are removed; 2 and 4 were not present anyway. The remaining set is {5, 6, 7, 9}, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
{5, 6, 7, 9}
Why is this the correct answer?
First form the union A ∪ B by listing every distinct element from A and B: A ∪ B = {1, 3, 5, 6, 7, 9}. The difference (A ∪ B) \ C removes every element that occurs in C. Since C = {1, 2, 3, 4}, the elements 1 and 3 are removed; 2 and 4 were not present anyway. The remaining set is {5, 6, 7, 9}, 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).
