If \(n(B-A)=21\) and \(n(A\cap B)=13\), what is \(n(B)\)?
Answer and explanation
Correct answer: 34
The set B is partitioned into two disjoint regions: elements only in B, represented by \(B-A\), and elements common to A and B, represented by \(A\cap B\). Therefore, \(n(B)=n(B-A)+n(A\cap B)=21+13=34\). Option C is correct. The value 21 omits the common elements, while 8 and 273 have no valid relation to the given partition.
Frequently asked questions
What is the correct answer to this question?
34
Why is this the correct answer?
The set B is partitioned into two disjoint regions: elements only in B, represented by \(B-A\), and elements common to A and B, represented by \(A\cap B\). Therefore, \(n(B)=n(B-A)+n(A\cap B)=21+13=34\). Option C is correct. The value 21 omits the common elements, while 8 and 273 have no valid relation to the given partition.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
