In a flour mill, 3 flour mills work for 8 hours and can grind 33.6 tons of flour. If 9 more mills of the same kind are added, how many hours will it take to grind 168 tons of flour.
某面粉厂3台磨面机工作8小时，能磨面33.6吨，如果再增加9台同样的磨面机，要磨出168吨面粉，需要多少小时．
<gadget id="calculator">33.6 / 3 / 8</gadget>
<output>1.4</output>

<gadget id="calculator">3 + 9</gadget>
<output>12</output>

<gadget id="calculator">1.4 * 12</gadget>
<output>16.8</output>

<gadget id="calculator">168 / 16.8</gadget>
<output>10</output>

<result>10</result>