Teacher Zhou hired two construction teams during the decoration. Engineering team A said: "Our engineering team contracted, and the task can be completed in 30 days." B Engineering team said: "Our engineering team contracted, and the task can be completed in 20 days." Teacher Zhou decided Let the two engineering teams decorate at the same time, so how many days can they complete the task of decorating the new house?
周老师装修时请了两个施工队，甲工程队说："我们工程队承包，30天能完成任务．"乙工程队说："我们工程队承包，20天能完成任务．"周老师决定让两工程队同时装修，这样多少天可以完成新房的装修任务？
<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>