The school bought a batch of books, including 310 story books and 240 literary books. These two books together accounted for 55% of the total number of books in this batch. How many books are there in this batch?
学校买一批书，其中有故事书310本，文艺书240本，这两种书共占这批书总数的55%，这批书有多少本？
<gadget id="calculator">310 + 240</gadget>
<output>550</output>

<gadget id="calculator">55 / 100</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">550 / (11/20)</gadget>
<output>1_000</output>

<result>1_000</result>