Question

Si n (A) = 18, n (B) = 12 y n (A U B) = 20, Calcula n (A n B).. Por favor lo necesito urgente

Answer 1

Se sabe que:
n(A U B) = n(A) + n(B) + n(A n B)
Por lo tanto
20 = 18 + 12 - n(A n B)
n(A n B) = 30 - 20
n(A n B) = 10

Answer 2

n(A) = 18
n(B) = 12
n(AuB)= 20  
* n(AuB)= n(A)+n(B) - n(A n B )
    20= 18 + 12 - n(AnB)
    n(AnB)= 10