Xiaohong reads a book, and reads 120 pages in 3 days, which is exactly (3/5) of the pages of the whole book. According to this calculation, how many days does it take her to read the whole book?
小红看一本书，3天看了120页，正好是全书页数的(3/5)，照这样计算，她看完全书一共需要多少天？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) / 3</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / (1/5)</gadget>
<output>5</output>

<result>5</result>