Mr. Wang went to swim in the swimming pool. The swimming lane of this swimming pool was 50 meters long. He swam 4 times in the swimming lane. How many meters did he swim in total?
王老师去游泳池游泳，这个游泳池的泳道长50米，他在泳道内游了4个来回，共游了多少米？
<gadget id="calculator">50 * 2 * 4</gadget>
<output>400</output>

<result>400</result>