For a book, Xiao Cong read (3/5) of the whole book on the first day, and 20 pages on the second day, accounting for exactly (1/6) of the whole book. How many pages did he read on the first day?
一本书，小聪第一天看了全书的(3/5)，第二天看了20页，正好占全书的(1/6)，第一天看了多少页．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">20 / (1/6)</gadget>
<output>120</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">120 * (3/5)</gadget>
<output>72</output>

<result>72</result>