A job can be completed by A alone in 10 hours, B by himself in 12 hours, and C by himself in 15 hours. If three people work together, how many hours can they complete half of the job?
一件工作甲独做10小时完成，乙独做12小时完成，丙独做15小时完成，若三人合作几小时可完成工作的一半？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<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">(1/2) / (1/4)</gadget>
<output>2</output>

<result>2</result>