The school library lends a batch of books to each class for reading. If each class borrows 50 books, the last class assigned can only borrow 45 books; if each class borrows 45 books, the remaining 95 books are returned. How many copies?
学校图书室将一批图书借给各班同学阅读，如果每班借50本，最后分到的一个班只能借到45本；如果每班借45本，还余下95本，这批图书有多少本？
<gadget id="calculator">95 + 5</gadget>
<output>100</output>

<gadget id="calculator">50 - 45</gadget>
<output>5</output>

<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">20 * 50</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 5</gadget>
<output>995</output>

<result>995</result>