Question

Sendo: n(A U B) = 20, n(A) = 15 e n(B) = 10, podemos afirmar que n(A ∩ B) É:
A) 0
B) 5
C) 10
D) 15
E) 45

Answer 1

n(A U B) = n(A) + n(B) - n(A ∩ B)

20 = 15 + 10 - n(A ∩ B)

n(A ∩ B) = 15 + 10 - 20

n(A ∩ B) = 25 - 20

n(A ∩ B) = 5

B) 5