If A⊆B, n(A)=34, and n(B)=82, what is n(B−A)?
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Answer and explanation
Correct answer: 48
Since A is a subset of B, every element of A is already included in B. The difference B−A therefore contains the elements of B that are not in A. For finite sets, n(B−A)=n(B)−n(A)=82−34=48. Thus 48 elements belong exclusively to B, and option A is the only correct answer.
Frequently asked questions
What is the correct answer to this question?
48
Why is this the correct answer?
Since A is a subset of B, every element of A is already included in B. The difference B−A therefore contains the elements of B that are not in A. For finite sets, n(B−A)=n(B)−n(A)=82−34=48. Thus 48 elements belong exclusively to B, and option A is the only 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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