Use a pan to cook cakes, and you can cook two cakes at the same time. If it takes 4 minutes to cook one cake (if it takes 2 minutes for the front and back), how many minutes should it be at least to cook three cakes?
用一只平底锅煎饼，每次能同时煎两张饼，如果煎一张饼需要4分钟(假如正反各需用2分钟)，煎3张饼至少多少分钟．
<gadget id="calculator">2 + 2 + 2</gadget>
<output>6</output>

<result>6</result>