It takes 10 days for engineering team A to repair a section of road alone, and 15 days for engineering team B to complete the repair alone. How many days will it take for team A and B to complete the repair together?
修一段公路，甲工程队单独修需要10天完成，乙工程队单独修需要15天完成，由甲乙两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 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<result>6</result>