Suppose that A and B are disjoint sets If there are 5 elemen

Suppose that A and B are disjoint sets. If there are 5 elements in A and 3 elements in B, how many elements are in the union of the two sets?

Would the correct answer be 8? Since they are still in the union of the two sets?

Solution

A ,B are disjont sets

n(A)=5

n(B)=3

n(AuB)=n(A)+n(B)-n(AintersettionB)

5+3-0

=8