A job can be done in 9 days (3/4), B can be done in 20 days (5/6), A and B work together for 6 days, and the rest of the work can be done by B alone. How much does it cost to complete this job? sky?
一件工作甲9天可以完成(3/4)，乙20天可以完成(5/6)，甲乙合做6天，剩下的工作由乙一人做完，问完成这件工作共花去多少天？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) / 9</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) / 20</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/12) + (1/24)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) * 6</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / (1/24)</gadget>
<output>6</output>

<gadget id="calculator">6 + 6</gadget>
<output>12</output>

<result>12</result>