Two brothers go from home to school at the same time, and the distance from home to school is 1000 meters. The older brother rides a bicycle at 200 meters per minute, and the younger brother walks at 50 meters per minute. On the way, the younger brother met the older brother who returned to pick up his homework immediately after arriving at school. How many minutes did the younger brother leave?
兄弟两人同时从家去学校，从家到学校的路程是1000米．哥哥骑自行车每分钟行200米，弟弟步行每分钟行50米．在途中，弟弟与到校后立即返回取作业的哥哥相遇，这时弟弟走了多少分钟？
<gadget id="calculator">200 + 50</gadget>
<output>250</output>

<gadget id="calculator">2 / 250</gadget>
<output>1/125 = around 0.008</output>

<gadget id="calculator">1_000 * (1/125)</gadget>
<output>8</output>

<result>8</result>