A batch of props needs to be produced for the National Day cultural performance. It takes 6 hours for male students to complete alone, and the work efficiency of female students is twice that of male students. How many hours can it be completed if male and female students work together?
迎国庆文艺汇演要制作一批道具，男同学单独完成需要6小时，女同学的工作效率是男同学的2倍，男女同学合做，多少小时可以完成？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) * 2</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/6) + (1/3)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / (1/2)</gadget>
<output>2</output>

<result>2</result>