A piece of work can be completed in 10 days by A and B, 12 days by B and C, and 15 days by A and C. Now the three are working together, how many days will it take to complete?
一件工作，甲、乙合做10天可以完成，乙、丙合作12天可以完成，甲、丙合做15天可以完成．现在三人合做，需要多少天才能完成？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

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

<gadget id="calculator">(1/10) + (1/12) + (1/15)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 2</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / (1/8)</gadget>
<output>8</output>

<result>8</result>