Each morning librarians place 560 books on a book shelf in the school library. Each student that visits library that day takes exactly 3 books from this shelf. Let s be the number of students which visit library on a particular day. Let b be the number of books left on the shelf at the end of that day. a. How does the number of books left on the shelf depend on number of students visiting library? Find formula for the function b(s).

b. There are 150 students studying in this school. Use this information to find the domain of the function b(s).