20% of a section of the road was repaired in 4 days. According to this calculation, how many days will it take to repair this road.
4天时间修了一段路的20%，照这样计算，修这条路一共需要多少天．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

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

<result>20</result>