The clock on the roof of Yongding Electric Power Building strikes 5 times at 5 o'clock, it takes 8 seconds, and it takes 12 times at 12 o'clock, how many seconds does it take.
永定电力大厦楼顶上的钟，5时敲5下，用了8秒，12时敲12下，需用时多少秒．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

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

<gadget id="calculator">2 * 11</gadget>
<output>22</output>

<result>22</result>