Xiaohong finished reading a story book in two days, and read 40% of the book on the first day, 15 pages less than the second day. How many pages does this book have?
小红两天读完一本故事书，第一天读了这本书的40%，比第二天少读15页．这本书共有多少页？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / (1/5)</gadget>
<output>75</output>

<result>75</result>