The engineering team completes (2/5) of a project in 3 days. According to this calculation, how many days will it take to complete the entire project.
工程队3天完成一项工程的(2/5)，照这样计算，做完全部工程需多少天．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 3</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 / (2/15)</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>