A project can be completed by A alone in 24 hours and by B in 36 hours. Now it requires 20 hours to complete, and the time for the two cooperation should be as little as possible. So, how many hours will A and B work together?
一项工程，甲独做24小时完成，乙独做36小时完成．现在要求20小时完成，并且两个合做的时间尽可能少．那么，甲、乙合做多少小时．
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 36</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">(1/6) / (1/36)</gadget>
<output>6</output>

<result>6</result>