It takes Xiaohong 18 seconds to climb from the first floor to the fourth floor. Xiaoming's speed is twice that of Xiaohong. How many seconds does it take for Xiaoming to climb from the first floor to the fourth floor?
小红的从一楼爬到四楼要18秒，小明的速度是小红的2倍，小明从一楼爬到四楼要多少秒．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<result>9</result>