目前公司有一笔很大的买卖，对所有图书提供15％的折扣，这个项目中，会计算一定数量的图书的应付金额、确定15％的折扣，扣除折扣并得到新的应付金额-打折后的金额-So far the company has a lot of the sale of all books offers a 15% discount, the project, calculate the number of books to cope with the amount of the 15% discount, After