If the wall clock strikes 5 times at 5 o'clock, it takes 20 seconds to complete the strike, so how many seconds does it take to strike 12 times at 12 o'clock?
挂钟5点钟敲5下，20秒敲完，那么12点钟敲12下，几秒敲完？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">5 * 11</gadget>
<output>55</output>

<result>55</result>