When Xiaoying reads a book, the number of pages she has read is 1/5 of the number of unread pages. If she reads another 30 pages, the ratio of the number of pages she has read to the number of unread pages is 3:5. How many pages are there?
小英读一本书，已读的页数是未读页数的(1/5)，如果再读30页，则已读页数与未读页数之比是3：5，这本书有多少页？
<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">30 / (5/24)</gadget>
<output>144</output>

<result>144</result>