Xiao Ming reads a story book, read 25% of the total pages on the first day, and the ratio of the number of pages read to the total pages on the second day is 2:5, 60 pages less on the first day than on the second day, How many pages does this book have?
小明看一本故事书，第一天看了总页数的25%，第二天看的页数与总页数的比是2：5，第一天比第二天少看了60页，这本书共有多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">60 / (3/20)</gadget>
<output>400</output>

<result>400</result>