Estimated sales Beginning inventory Average selling price Variable production costs Fixed production costs 15,000 books 0 books $76 per book $45 per book $285,000 per semester The fixed-cost allocation rate is based on expected sales and is therefore equal to $285,00015,000 books =$19 per book . Global Press produces textbooks for high school accounting courses. The company recently hired a new editor, Jaden Green, to handle production and sales of books for an introductory accounting course. Jaden's compensation depends on the gross margin associated with sales of this book. Jaden needs to decide how many copies of the book to produce. The following information is available for the fall semester 2020: (Click the icon to view the information.) Jaden has decided to produce either 15,000,21,000, or 31,500 books. Calculate the gross margin for each level of production. Begin with 15,000 books, then 21,000 books, and lastly 31,500 books. (Enter a " 0 " for any zero balance accounts. If an account does not have a variance, do not select a label.)