There are 15 pots of flowers placed every 2 meters in a circular flower bed. What is the circumference of the flower bed in meters?
一个圆形花坛每隔2米摆一盆花一共摆了15盆，花坛的周长是多少米．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>