A project, if A is alone, can be completed within the time specified in the plan; if B is alone, it will take 3 days to complete; It was also completed within the time stipulated in the plan. How many days will it take to complete the project.
一项工程，如果由甲单独，正好在计划规定的时间内完成；如果由乙单独做，要超过规定时间3天才能完成；如果先由甲乙合作2天后，其余的再由乙单独做，正好也在计划规定的时间内完成．完成这项工程计划用多少天．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 / (1/3)</gadget>
<output>6</output>

<result>6</result>