To build a road, it was originally planned that 60 people would work in 80 days to complete it. Now after these 60 people have worked for 20 days, the remaining part has been increased by 30 people to continue working. How many more days can it be completed?
修一条公路，原计划60人工作80天完成．现在这60人工作20天后，剩下的部分又增加了30人继续工作，这样再用多少天可以完成？
<gadget id="calculator">20 / 80</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 60 / 80</gadget>
<output>1/4_800 = around 0.000208</output>

<gadget id="calculator">60 + 30</gadget>
<output>90</output>

<gadget id="calculator">(1/4_800) * 90</gadget>
<output>3/160 = around 0.01875</output>

<gadget id="calculator">(3/4) / (3/160)</gadget>
<output>40</output>

<result>40</result>