trash can is placed every 10 meters on the road around the lake, and there are 30 trash cans in total. How long is it around the lake?
在环形湖路上每隔10米放置1个垃圾桶，共放了30个．环湖长多少米？
<gadget id="calculator">30 * 10</gadget>
<output>300</output>

<result>300</result>