英语翻译请翻译并解答 In the library of Hope School,there is a bookshelf,whi_英语解答

英语翻译
请翻译并解答 In the library of Hope School,there is a bookshelf,which contains two layers:the upper and the lower.There are 245 books in all on the shelf.Everyday,15 books on the upper layer are checked out,and three days later,the number of the books remaining on the two layers is equal.Please respectively calculate the original number of the books on the two layers of the bookshelf.

人气：189 ℃　时间：2020-05-01 01:44:59

解答

在希望小学的图书管里有一个书架.这个书架有两层：上层和下层.在书架上一共有245本书.每天上层的15本书会借出.三天后,这两层上剩余书本的数量就一样了.请分别计算两层书架上原来各有多少书.
原来是数学题啊请问你会解答吗？设上层书架原来有书X，下层Y给你两个方程：1.X-45=Y2.X+Y=245X=145,Y=100过程1.X-15*3=Y得出X=Y+45,将这个带入X+Y=245 得出 Y+45+Y=245 得出Y=100，X=145你明白吗？