One job can be done by A in 30 hours and by B in 20 hours. Two people work together, and A leaves for 5 hours due to something, and B does not stop, how long did it take to complete the task?
一件工作，甲独做30小时完成，乙独做20小时完成．两人合作，中途甲因事离开了5小时，乙没有间断，完成任务时共用了多长时间？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 5</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

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

<gadget id="calculator">(3/4) / (1/12)</gadget>
<output>9</output>

<gadget id="calculator">9 + 5</gadget>
<output>14</output>

<result>14</result>