One piece of work can be completed by A alone in 12 hours, and by B alone in 8 hours; if calculated according to this work efficiency, how many hours will it take for A and B to complete the work together?
一件工作，甲单独做要12小时可以完成，乙单独做要8小时可以完成；如果按这样的工作效率计算，由甲、乙两人一起做，完成这件工作需要时间是多少小时
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/12) + (1/8)</gadget>
<output>5/24 = around 0.208333</output>

<gadget id="calculator">1 / (5/24)</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>