Question

Berapa rumah tangga memakai ketiga macam sabun cuci tersebut ?

Answer 1

N(S) = n(A) + n(B) + n(C) - (n(AB)+n(BC)+n(AC)-n(ABC))
500 = 275 + 240 + 325 - (125+55+190- n(ABC))
500 = 840 - 370 + n(ABC)
500 = 470 + n(ABC)
n(ABC) = 500 - 470
n(ABC) = 30

Jadi ada 30 rumah tangga yg memakai ketiga macam sabun cuci tersebut.

semoga membantu :)

Answer 2

N(S) = n(A) + n(B) + n (C) - 2n(A n B)- 2n(A n C) - 2n(B n C)- 3n (A n B n C)
3n (A n B n C) = n (S) - (n(A) + n(B) + n (C) - 2n(A n B)- 2n(A n C) - 2n(B n C))
                     = 500 - (275+240+325-250-280-110)
                     = 500 - 200
                     = 300
n (A n B n C)  = 300/3 = 100