Question

A) se n(A)=20, n(B)=25, n(A∩B)=8 B) se n(AUB)=34, n(a)=23 e n(B)=18

Answer 1

A)

N(A ∪ B) = n(A) + n(B) - n(A ∩ B)

n(A ∪ B) = 20 + 25 - 8

n(A ∪ B) = 45 - 8

n(A ∪ B) = 37

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B)

n(A ∪ B) = n(A) + n(B) - n(A ∩ B)

34 = 23 + 18 - n(A ∩ B)

34 = 41 - n(A ∩ B)

34 - 41 = - n(A ∩ B)

- 7 = - n(A ∩ B)

n(A ∩ B) = 7