For a project, a certain engineering team completed 20% of the project in 7 days. According to this calculation, how many days will it take to complete the project.
一项工程，某工程队干了7天完成了工程的20%，照这样计算，完成这项工程还需要多少天．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/5) / 7</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">(4/5) / (1/35)</gadget>
<output>28</output>

<result>28</result>