A file has been downloaded to 65%, and it takes 13 minutes in total. At this speed, how many minutes will it take before the download is complete.
一份文件下载到了65%，共需13分钟，照这样的速度，还要等多少分钟才下载完毕．
<gadget id="calculator">65 / 100</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">13 / (13/20)</gadget>
<output>20</output>

<gadget id="calculator">20 - 13</gadget>
<output>7</output>

<result>7</result>