It takes 9 days to build a canal if you work 8 hours a day. If the work efficiency remains the same and you work 6 hours a day, how many days can you complete the task? (Solve with ratio)
修一条水渠，每天工作8小时，要9天完成，如果工作效率不变，每天工作6小时，多少天可以完成任务？(用比例解)
<gadget id="calculator">8 * 9</gadget>
<output>72</output>

<gadget id="calculator">72 / 6</gadget>
<output>12</output>

<result>12</result>