Xiaohong reads a story book, reads half of the book on the first day, reads the remaining half more than 10 pages on the second day, and finishes reading 20 pages on the third day. How many pages does this storybook have?
小红看了一本故事书，第一天看了这本书得一半，第二天又看了余下的一半多10页，第三天看了20页正好看完．这本故事书共有多少页？
<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">60 * 2</gadget>
<output>120</output>

<result>120</result>