When using a pan to pancake, only 2 pancakes can be baked at most at a time, and both sides must be baked for 3 minutes on each side. How many minutes is the fastest time to bake 4 cakes?
用平底锅烙饼，每次最多只能烙2张饼，两面都要烙，每面3分钟．烙4张饼最快用多少分钟完成．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

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

<result>12</result>