It takes 6 people to work 4 hours a day for 5 days to complete a project. According to this calculation, if 4 more people are added and 1 hour is reduced every day, how many days can be completed in advance.
一项工程，6人每天工作4小时要5天才能完成．照这样计算，如果增加4人，每天减少1小时，可提前多少天完成．
<gadget id="calculator">1 / 6 / 4 / 5</gadget>
<output>1/120 = around 0.008333</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">(1/120) * 10 * 3</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<result>1</result>