My mother uses a pan that can bake two cakes at the same time. Both sides of the cake need to be baked. It takes 3 minutes to bake each side. Now I need to bake 3 cakes. How long does it take at least?
妈妈用同时能烙两张饼的锅烙饼，饼的两面都要烙，每烙完一面需要3分钟，现在需要烙3张饼，最少需要多少分钟．
<gadget id="calculator">3 + 3 + 3</gadget>
<output>9</output>

<result>9</result>