Wang Hong's home is 10 kilometers away from the school. He rides to school every morning at a speed of 250 meters per minute, and he arrives at school on time. One morning, because of the headwind, the wind speed is 50 meters per minute. He is still riding at a speed of 250 meters per minute for the first 4 kilometers. Then, for the remaining 6 kilometers, how many meters per minute should he be able to arrive on time? school?
王红的家离学校10千米，他每天早晨骑车上学都以每分钟250米的速度骑，正好能准时到校．一天早晨，因为逆风，风速为每分钟50米，开始4千米，他仍以每分钟250米的速度骑，那么，剩下的6千米，他应以每分钟多少米的速度才能准时到校？
<gadget id="calculator">1_000 / 250</gadget>
<output>4</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<gadget id="calculator">250 - 50</gadget>
<output>200</output>

<gadget id="calculator">1_000 / 200</gadget>
<output>5</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">40 - 20</gadget>
<output>20</output>

<gadget id="calculator">1_000 / 20</gadget>
<output>50</output>

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

<gadget id="calculator">300 + 50</gadget>
<output>350</output>

<result>350</result>