A project can be completed in 20 days alone, and B can be completed in 30 days alone. Now two people are working together, A takes a break for 1 day, and B takes a rest for 6 days. When the project is completed, how many days did they work at the same time?
一件工程甲独做20天完成，乙独做30天完成．现由二人合做，中途甲先休息1天，乙接着休息6天，工程完成时，两人同时工作了几天？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

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

<gadget id="calculator">(1/30) * 6</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/20) + (1/5)</gadget>
<output>5/4 = around 1.25</output>

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

<gadget id="calculator">(5/4) / (1/12)</gadget>
<output>15</output>

<gadget id="calculator">15 - 1 - 6</gadget>
<output>8</output>

<result>8</result>