Three workers, A, B, and C, complete a certain job independently. It takes 25 days for A to do it alone, 20 days for B to do it alone, and 15 days for C to do it alone. How many days will it take for three people to work together to complete (1/3) of all the work?
甲、乙、丙三个工人单独完成某种工作，甲单独做需要25天，乙单独做需要20天，丙单独做需要15天．三个人合作，要完成全部工作的(1/3)，需要多少天？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 25</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/25) + (1/20) + (1/15)</gadget>
<output>47/300 = around 0.156667</output>

<gadget id="calculator">(1/3) / (47/300)</gadget>
<output>100/47 = around 2.12766</output>

<result>100/47 = around 2.12766</result>