A and B work together to do a job. After 8 days of cooperation, B does it alone for 5 days, leaving (1/6) of the job. It is known that it will take 30 days for B to complete the job alone, and A will complete the job alone. How many days do you work?
甲、乙合做一件工作，合作8天后，乙又独做5天，还剩下这件工作的(1/6)，已知乙单独完成这件工作要30天，甲单独完成这件工作要多少天？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

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

<gadget id="calculator">(1/30) * 13</gadget>
<output>13/30 = around 0.433333</output>

<gadget id="calculator">1 - (1/6) - (13/30)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 8</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / (1/20)</gadget>
<output>20</output>

<result>20</result>