One pot can cook 15 dumplings at a time, and it takes 6 minutes to cook one dumpling. What is the fastest time to cook 30 dumplings in one pot?
一只锅一次可以煮15个水饺，煮熟一个水饺要6分钟．一只锅煮熟30个水饺最快要多少分钟．
<gadget id="calculator">30 / 15</gadget>
<output>2</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>