In a story book, Xiaohong read 20% of the whole book on the first day, and read 15 more pages on the second day than on the first day. At this time, she still didn’t read half of the book. How many pages does the book have?
一本故事书，小红第一天读了全书的20%，第二天比第一天多读了15页，这时还有一半没读，这本书一共有多少页？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/2) - (1/5) - (1/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">15 / (1/10)</gadget>
<output>150</output>

<result>150</result>