Two classes of students participated in the book donation activity and donated a batch of books. The books donated by the first class were 100 more than the total (3/10), and the books donated by the second class were 50 less than the total (3/5). Book. How many books do you ask the two classes to donate?
有两个班的同学参加捐书活动，共捐一批图书，一班同学捐的图书比总数的(3/10)多100本，二班捐的图书比总数的(3/5)少50本．求两个班共捐多少本图书？
<gadget id="calculator">100 - 50</gadget>
<output>50</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/10) - (3/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">50 / (1/10)</gadget>
<output>500</output>

<result>500</result>