An airplane flies 18 kilometers per minute. At this speed, how many kilometers will the airplane fly in half an hour?
一架飞机每分钟飞行18千米，照这样的速度，半小时这架飞机将飞行多少千米．
<gadget id="calculator">18 * 30</gadget>
<output>540</output>

<result>540</result>