Xiaoming’s family has a pan that can fry 3 pancakes at a time. Now Xiaoming’s mother wants to fry 19 pancakes, and each pancake needs to be fried for 2 minutes (1 minute for the front side and 1 minute for the reverse side). How many minutes does it take at least 19 cakes.
小明家有一只平底锅，一次可以煎3只饼，小明妈妈现在要煎19只饼，每只饼要煎2分钟(正面要煎1分钟，反面也要煎1分钟)，小明妈妈煎好这19只饼最少要用多少分钟．
<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">10 + 3</gadget>
<output>13</output>

<result>13</result>