There are 3,000 science books in the school library, accounting for 15% of the total number of books in the school. How many books are there in the school library?
学校图书馆共有科学书3000本，占学校图书总数的15%，学校图书馆共有多少本书．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">3_000 / (3/20)</gadget>
<output>20_000</output>

<result>20_000</result>