If A ⊆ B, n(A) = 5, and n(B) = 12, what is n(A ∪ B)?
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Answer and explanation
Correct answer: 12
The relation A ⊆ B means every element of A is already an element of B. Taking the union of A and B therefore adds no new elements beyond B, so A ∪ B = B. Consequently, n(A ∪ B) = n(B) = 12, making option C the correct answer.
Frequently asked questions
What is the correct answer to this question?
12
Why is this the correct answer?
The relation A ⊆ B means every element of A is already an element of B. Taking the union of A and B therefore adds no new elements beyond B, so A ∪ B = B. Consequently, n(A ∪ B) = n(B) = 12, making option C the correct answer.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Venn Diagrams.
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