The pan can only bake two cakes at a time, and both sides need to be baked. Each side takes 50 seconds. How many seconds does it take for mother to bake five cakes?
平底锅每次只能烙两张饼，两面都要烙，每面需要50秒，妈妈要烙5张饼需要多少秒．
<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">50 * 3</gadget>
<output>150</output>

<gadget id="calculator">100 + 150</gadget>
<output>250</output>

<result>250</result>