Xiaoqiang reads a science and technology book. He reads 20 pages on the first day and 25 pages on the second day. He just reads the whole book (3/7) in two days. How many pages does this science book have?
小强看一本科技书，第一天看了20页，第二天看了25页，两天正好看了全书的(3/7)，这本科技书有多少页？
<gadget id="calculator">20 + 25</gadget>
<output>45</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">45 / (3/7)</gadget>
<output>105</output>

<result>105</result>