If \(A=\{\text{red},\text{blue},\text{green}\}\) and \(B=\{\text{blue},\text{yellow}\}\), what is \(A\cup B\)?
Answer and explanation
Correct answer: \(\{\text{red},\text{blue},\text{green},\text{yellow}\}\)
The union contains every distinct element appearing in either set. From A we take red, blue, and green; from B we add yellow. Blue appears in both sets, but a set lists an element only once. Therefore, \(A\cup B=\{\text{red},\text{blue},\text{green},\text{yellow}\}\). Option B is only the intersection, not the union.
Frequently asked questions
What is the correct answer to this question?
\(\{\text{red},\text{blue},\text{green},\text{yellow}\}\)
Why is this the correct answer?
The union contains every distinct element appearing in either set. From A we take red, blue, and green; from B we add yellow. Blue appears in both sets, but a set lists an element only once. Therefore, \(A\cup B=\{\text{red},\text{blue},\text{green},\text{yellow}\}\). Option B is only the intersection, not the union.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
