When Xiaoqin reads a book, the ratio of the number of pages she has read to the number of pages she has not read on the first day is 3:5, and she reads 42 pages on the second day. At this time, the number of pages she has read is equal to the number of pages she has not read , how many pages does this book have?
小琴看一本书，第一天看的页数和未看的页数之比是3：5，第二天又看了42页，这时已看的页数和未看的页数相等，这本书有多少页？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(1/2) - (3/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">42 / (1/8)</gadget>
<output>336</output>

<result>336</result>