Xiaojun swam 4 back and forth in the swimming pool and swam 400 meters in total. How long is the swimming lane in this swimming pool?
小军在泳池游4个来回，共游了400米，这个泳池的泳道长多少米
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">400 / 8</gadget>
<output>50</output>

<result>50</result>