job A and B together take 8 hours to complete, and B and C work together in 6 hours. Now ask A and C to work together for 3 hours, and B needs to complete the remaining 9 hours. How many hours will it take for B to finish the job alone?
一件工作，甲、乙合做需8小时完成，乙、丙合做需6小时完成．现在先请甲、丙合做3小时后，余下的乙还需做9小时完成，那么如果由乙单独做完这件工作需要多少小时？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/8) + (1/6)</gadget>
<output>7/24 = around 0.291667</output>

<gadget id="calculator">(7/24) * 3</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">1 - (7/8)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<gadget id="calculator">(1/8) / 3</gadget>
<output>1/24 = around 0.041667</output>

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

<result>24</result>