A project alone takes 14 hours, and B alone takes 20 hours. If A works for 1 hour, B takes over from A for 1 hour, and then A takes over from B for 1 hour...the two work alternately in this way, ask: complete the task How many hours will it take?
一项工程，甲单独做要14小时，乙单独做要20小时，若甲做1小时后乙接替甲做1小时，再由甲接替乙做1小时…两人如此交替工作，问：完成任务共需多少小时？
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">1 / 14</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/14) + (1/20)</gadget>
<output>17/140 = around 0.121429</output>

<gadget id="calculator">(17/140) * 8</gadget>
<output>34/35 = around 0.971429</output>

<gadget id="calculator">1 - (34/35)</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">(1/35) / (1/14)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">16 + (2/5)</gadget>
<output>82/5 = around 16.4</output>

<result>82/5 = around 16.4</result>