The wall clock at the train station strikes 3 times at 3 o'clock and takes 6 seconds. How many seconds does it take to knock 10 times at 10 o'clock?
火车站的挂钟，3点敲3下，用时6秒．10点敲10下，用时多少秒．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">3 * 9</gadget>
<output>27</output>

<result>27</result>