7. Prentice Hall wants to reduce a large stock of Quantitative Analysis books from their warehouse. They have offered the JU Bookstore a quantity discount pricing schedule, as follows: Assuming the annual demand rate is 400 books, the ordering cost is $20, and the annual holding cost is $3 per textbook, answer the following: 7a) What should your order size be if you want to minimize total cost? 7b) What is the minimum TOTAL ANNUAL COST