pake cara nya juga yah kak
Jawab:
n(B) = 20
___
n(S) = 40
n(A) = 22
n(A n B ) = 9
n(AUB)^c = 7
n(S) + n(A n B ) = n(A) + n(B) + n(AUB)^c
40 + 9 = 22+ n(B) + 7
49 = 29 + n (B)
n(B) = 49 - 29
n(B) = 20
