Question

A, B are disjoint sets, if n(A U B)
= 15, n (A) = 9, then find n(B).​

Answer 1

Answer:

As the sets are disjoint,the no. of elements in the intersection is zero. So,

n(AUB)=n(A)+n(B)

=>15=9+n(B)

=>n(B)= 15-9=6

Therefore n(B)=6