Students in a university are allowed to buy either lunch or dinner in a student's canteen. There are freshmen students in total. Altogether freshmen students buy the lunch or dinner. From this amount, students buy just one meal. The number of freshmen students which buy lunch is bigger by
than the number of freshmen students which buy dinner. How many freshmen students buy only the dinner?
Students from a class decided to order books for forthcoming holiday. The book-shop in the neighborhood had two bestsellers on the stock: a crime novel and a horror stories. There were students in the class in total. From this total, students bought horror stories. Altogether students bought just one of the books. Two students did not buy any of these books. How many students bought the crime novel?
There are two types of cheese in a shop. Altogether customer were in the shop during a day. From this total, customers bought the first cheese. From the same total, customers bought the second cheese. of customers which bought at least one of the types of cheese bought actually both types. How many customers did not buy any of these two cheeses?