Question

.If n(A) = 15, n(A U B) =30, n(A ∩ B) = 8, then n(B) =?​

Answer 1

Answer:

n(a)=15, only a is 5

n(a ∪ b)=8,  means all are 30

n(b)=8, means there common is 8

n(B)=n(A ∪ B) - n(A) - n(A ∩ B)

n(B)=30           -15     -8

n(B)=7

answer is 7