A swimming pool is 50 meters long, and Li Ming can swim 3 back and forth each time. How many meters can Li Ming swim each time?
一个游泳池长50米，李明每次能游3个来回．李明每次能游多少米？
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">50 * 6</gadget>
<output>300</output>

<result>300</result>