Use a pan to fry pancakes, and only two pancakes can be fried at the same time. If it takes 4 minutes to cook one cake (2 minutes for the front and back sides), then how many minutes should it take to cook 5 cakes?
用一只平底锅煎饼，每次只能同时煎两张饼．如果煎一张饼需4分钟(正反面各需2分钟)，那么煎5张饼至少需要多少分钟．
<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<result>10</result>