If n(A ∪ B) = 96, n(A) = 58, and n(B) = 49, find n(A ∩ B).
Answer and explanation
Correct answer: 11
For two finite sets, the inclusion-exclusion formula is n(A ∪ B) = n(A) + n(B) − n(A ∩ B). Substituting the given values gives 96 = 58 + 49 − n(A ∩ B). Therefore, n(A ∩ B) = 107 − 96 = 11. The subtraction removes the double counting of common elements, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
11
Why is this the correct answer?
For two finite sets, the inclusion-exclusion formula is n(A ∪ B) = n(A) + n(B) − n(A ∩ B). Substituting the given values gives 96 = 58 + 49 − n(A ∩ B). Therefore, n(A ∩ B) = 107 − 96 = 11. The subtraction removes the double counting of common elements, so option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Venn Diagrams.