There are 3000 science and technology books and story books in the school library, of which 25 are science and technology books. Because students like reading books on science and technology, they buy some books on science and technology, which account for 35% of the total. Later, the school bought several science and technology books.

Test center: grade four compound application questions.

Analysis: This problem can be solved by an equation. Suppose the school later bought X science and technology books, and the total number of books became 3000+x, and there were (3000+x)×( 1-35) story books. In this process, the number of story books has not changed, which is 3000×( 1-25).

Solution: Solution: Set up a school and buy X science and technology books, and you can get the equation:

(3000+x)×( 1-35)= 3000×( 1-25)

(3000+x)×25=3000×35，

1200+25x= 1800，

25x=600，

x= 1500。

A: The school later bought 1500 science and technology books.