Xiaohong reads a book. She reads 15 pages on the first day and 5 pages more than the second day. It is known that she reads the whole book (1/7) on the second day. How many pages are there in the whole book?
小红读一本书，第一天读了15页，比第二天多读5页，已知第二天读了全书的(1/7)，全书有多少页？
<gadget id="calculator">15 - 5</gadget>
<output>10</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">10 / (1/7)</gadget>
<output>70</output>

<result>70</result>