The ratio of the number of pages read to the number of unread pages is 1:5. If you read 20 pages later, the ratio of the number of pages read to the number of unread pages is 3:5. How many pages does this book have?
已读页数与未读页数之比为1：5．如果再读20页以后，则已读页数与未读页数之比为3：5．这本书共有多少页？
<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 + 5</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(3/8) - (1/6)</gadget>
<output>5/24 = around 0.208333</output>

<gadget id="calculator">20 / (5/24)</gadget>
<output>96</output>

<result>96</result>