I borrowed a fairy tale book from the library on Sunday. I read 12 pages a day. I read half of the book in 16 days. After that, I read 24 pages a day. I just finished reading it within the borrowing period. How many days is the borrowing period for this book?
星期天我从图书馆借来一本童话书，每天看12页，16天看了这本书的一半，以后每天看24页，正好借期内看完，这本书的借期是多少天？
<gadget id="calculator">16 / 24</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">12 * (2/3)</gadget>
<output>8</output>

<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<result>20</result>