Question 1
The complement of set B is all the elements in S but that are not in B, which is [tex]\{2, 4, 5, 9, 10, 11, 12, 13, 14, 17, 19\}[/tex].
We want to find the intersection of set A and the complement of set B, which is the set of all elements that both sets contain.
This is {2, 9, 10, 12}, meaning there are 4 elements.
Question 2
Following a similar logic as the last problem, the complement of set A is [tex]\{1,3,4,5,6,7,11,13,14,15,17,18,19\}[/tex].
Therefore, the desired set is [tex]\{1,3,6,7,15,18\}[/tex], and thus there are 6 elements.
