It takes 4 seconds for the bells in the Bell and Drum Towers to strike 5 times at 5 o'clock. How many seconds does it take to type 10 times at 10 o'clock in the evening?
钟鼓楼的锺打点报时，5点锺打5下需要4秒钟．问晚上10点时打10下需要多少秒钟？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

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

<gadget id="calculator">9 * 1</gadget>
<output>9</output>

<result>9</result>