After a project was started as planned (3/5), the daily work efficiency increased by 40%, but the number of people decreased (1/5), so it took 67 days to complete all tasks. How many days will it take for this project to be completed if everything goes according to plan?
一项工程，开始按计划做了(3/5)后，每天工效提高40%，但人数减少(1/5)，这样完成全部任务时共用了67天．问这件工程如果全部按计划去做需要几天完工？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">1 / 5</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">(7/5) * (4/5)</gadget>
<output>28/25 = around 1.12</output>

<gadget id="calculator">(2/5) / (28/25)</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">(3/5) + (5/14)</gadget>
<output>67/70 = around 0.957143</output>

<gadget id="calculator">67 / (67/70)</gadget>
<output>70</output>

<result>70</result>