A story book has been read (3/7), and the number of unread pages is 15 more than the number of read pages. How many pages does this book have?
一本故事书，已读了(3/7)，未读页数比已读页数多15页．这本书有多少页？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7) - (3/7)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">15 / (1/7)</gadget>
<output>105</output>

<result>105</result>