Each time a politician or celebrity writes a book, bookstores can expect at least some customers to want the book, but whether or not it will become a best seller is less certain. the bookstore's primary inventory management challenge is

Having enough books to satisfy customer demands versus the cost of having the inventory.

It is not possible to know for sure whether or not a book will become a best seller. Therefore, the biggest management challenge for bookstores when setting the inventory is to have a number of books that will be enough to satisfy all the customer demands without dealing with the cost of having the inventory.  

it is a better alternative

the last day of school because i didn’t have to go to school the next day