The width of a rectangular swimming pool is 30 meters, and the length is 6 times the width. Xiao Ming swam around the swimming pool. How many meters did he swim?
一个长方形游泳池的宽是30米，长是宽的6倍，小明绕游泳池游了一圈，他游了多少米？
<gadget id="calculator">30 * 6</gadget>
<output>180</output>

<gadget id="calculator">180 + 30</gadget>
<output>210</output>

<gadget id="calculator">210 * 2</gadget>
<output>420</output>

<result>420</result>