project, A completed (1/4) of this project in 5 days, how many days will it take A alone to complete this project.
一项工程，甲5天完成了这项工程的(1/4)，甲独做需要多少天才能完成这项工程．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 5</gadget>
<output>1/20 = around 0.05</output>

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

<result>20</result>