A project, A and B cooperate to complete in 8 days. If you let A do it for 6 days first, and then B can do it alone for 9 days to complete the task. How many days will it take B to do the project alone?
一项工程，甲乙合作8天完成．如果让甲先做6天，然后乙再独做9天可以完成任务．那么乙独做这项工程要多少天．
<gadget id="calculator">6 / 8</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">9 - 6</gadget>
<output>3</output>

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

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

<result>12</result>