The traffic lights at Junction 3 change every 30 seconds. So how many times did the signal switch between 8:00 am and 8:20 am?
三号路口的交通信号灯每30秒转换一次．那么从上午8点到8点20分之间，这个信号灯一共转换了多少次？
<gadget id="calculator">1_200 / 30</gadget>
<output>40</output>

<gadget id="calculator">40 + 1</gadget>
<output>41</output>

<result>41</result>