Xiaoqiang reads a story book. After 14 days of reading, there are still 80 pages left; when he reads it for 21 days, the ratio of the number of remaining pages to the total number of pages is 1:8. How many pages are there in this book?
小强看一本故事书，看了14天时，还剩80页；当他看了21天时，剩下的页数与总页数的比是1：8，这本书共多少页？
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 / 8 / 21</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/24) * 14</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">1 - (7/12)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">80 / (5/12)</gadget>
<output>192</output>

<result>192</result>