When using a pan to bake pancakes, only two sheets can be baked at a time, both sides must be baked, each side needs to be baked for 4 minutes, and 5 cakes are to be baked, how many minutes can be baked at the fastest.
用平底锅烙饼，每次只能烙两张，两面都要烙，每面要烙4分钟，要烙5张饼，最快多少分钟可以烙完．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<result>20</result>