It takes 10 days for team A to complete the repair alone, 12 days for team B to complete the repair alone, 15 days for team C to complete the repair alone, and how many days will it take for team A, B, and C to repair it together?
一段公路，甲队单独修要10天完成，乙队单独修要12天完成，丙队单独修要15天完成，甲、乙、丙三队合修，需要几天完成？
<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 / (1/4)</gadget>
<output>4</output>

<result>4</result>