Three people A, B, and C do a job. If each person takes turns to do it in the order of A, B, and C, it happens to be completed in a whole number of days, and it is B who finishes the job; if the order of B, C, and A is followed If you do it in turn, it will take (1/2) more days than the plan; if you do it in turn in the order of C, A, and B, it will take (1/3) more days than the plan. It is known that it will take 9 days for A to complete this task alone. If A, B, and C do this task together, how many days will it take to complete it.
甲、乙、丙三人做一件工作，若按照甲、乙、丙的顺序每人一天轮流去做，恰好整数天做完，并且结束工作的是乙；若按乙、丙、甲的顺序轮流去做，则比计划多用(1/2)天；若按丙、甲、乙的顺序轮流去做，则比计划多用(1/3)天．已知甲单独做完这件工作要9天，若甲、乙、丙三人一起做这件工作，则要用多少天才能完成．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(1/2) / (2/3)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 + (1/2) + (3/4)</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">9 / (9/4)</gadget>
<output>4</output>

<result>4</result>