Xingfu Village is going to build a road. If Team A alone takes 30 days to complete the construction, and Team B alone takes 20 days to complete the construction, now how many days will it take for Team A and Team B to complete the construction together?
幸福村准备修一条公路，如果让甲队单独修完要用30天完成，乙队单独修完要用20天完成，现在由甲乙两队合修，则需要几天修完？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

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

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

<result>12</result>