A cafeteria serves only main courses and desserts. Some people just have a main,
some have just a dessert and some have both.
One day, 65% of the customers had a main course and 90% had a dessert.
a) Show this information on a Venn diagram.
b) What is the probability that a customer had a main course and a dessert? c) If it is known that a customer had a dessert, what is the probability that
they also had a main course?