Question Detail
Question
What is the cardinality of A ∪ B if n(A) = 10, n(B) = 15, and n(A ∩ B) = 5?
Correct Answer
Option B is the correct answer.
Detailed Explanation
n(A ∪ B) = n(A) + n(B) - n(A ∩ B) = 10 + 15 - 5 = 20.
Hint
The notes indicate answer B.