A road repair team builds a road. Team A completes the repair in 20 days alone, and Team B completes the repair in 30 days alone. How many days does it take for the two teams to complete the repair together?
修路队修一条公路，甲队独修20天完成，乙队独修30天完成，两队合修几天才能修完？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<result>12</result>