There is a collection of books in the school library. After lending out 65%, another 540 books are purchased. At this time, the existing books are equal to the borrowed books. How many books are there in school books?
学校图书室有一批藏书，借出65%后，又购进540本，这时现有的书和借出的书相等．学校图书是原有多少本书？
<result>1_800</result>