A5. In a workshop on healthy eating, 11 people gathered. They talked about fruits and vegetables. Three of them do not like either fruits or vegetables. Four like fruits but not vegetables. Five of them like fruits. How many of them like both fruits and vegetables?
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
A5. Let $S$ be the set of people who like fruit and $Z$ be the set of people who like vegetables. We know: $|S|=5$ and $|S-Z|=4$ from this it follows that $|S \cap Z|=1$.