Read a story book, read the whole book (1/5) on the first day, and read 6 pages more than the first day on the second day. At this time, the ratio of the number of pages read to the number of remaining pages is 9:11. How many pages does this book have?
读一本故事书，第一天读了全书的(1/5)，第二天比第一天多读6页，这时已读的页数与剩下页数的比是9：11，这本书共有多少页？
<gadget id="calculator">11 + 9</gadget>
<output>20</output>

<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(9/20) - (1/5) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">6 / (1/20)</gadget>
<output>120</output>

<result>120</result>