If U = {1,2,3,4,5,6,7,8}, A = {1,3,5,7}, and B = {2,3,5,8}, what is A ∪ B?
Answer and explanation
Correct answer: {1,2,3,5,7,8}
The union A ∪ B contains every element that belongs to A, to B, or to both, with repeated elements written only once. Combining A = {1,3,5,7} and B = {2,3,5,8} gives {1,2,3,5,7,8}. The elements 3 and 5 are common, but they are listed once. The universal set U provides the surrounding set of possible elements but does not change the union calculation.
Frequently asked questions
What is the correct answer to this question?
{1,2,3,5,7,8}
Why is this the correct answer?
The union A ∪ B contains every element that belongs to A, to B, or to both, with repeated elements written only once. Combining A = {1,3,5,7} and B = {2,3,5,8} gives {1,2,3,5,7,8}. The elements 3 and 5 are common, but they are listed once. The universal set U provides the surrounding set of possible elements but does not change the union calculation.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
