The ticket for the railway swimming pool is 30 yuan per person per time, and the length of the swimming pool lane is 50 meters. Xiao Ming swam 4 times, how many meters did he swim in total?
铁路游泳馆的门票是每人每次30元，游泳池泳道的长度是50米，小明游了4个来回，一共游了多少米？
<gadget id="calculator">50 * 2 * 4</gadget>
<output>400</output>

<result>400</result>