Mom wants to bake 3 cakes, but only 2 cakes can be baked at a time, and both sides must be baked, and each side is baked for 3 minutes. How many minutes does it take for mother to bake the cakes?
妈妈要烙3张饼，每次只能烙2张饼，两面都要烙，每面烙3分钟，妈妈至少要用多少分钟才能烙好饼．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<result>9</result>