A and B are practicing race walking on a 400-meter circular track. They start at the same time. A is behind B at the start. After 6 minutes, A passes B for the first time, and A passes B for the second time in 30 minutes. Assuming that the speed of the two remains the same, how many meters is A behind B when starting?
甲乙二人在400米环形跑道上练习竞走，两人同时出发，出发时甲在乙后面，出发后6分钟，甲第一次超过乙，30分钟时甲第二次超过乙．假设两人速度不变，那么出发时甲在乙后面多少米？
<gadget id="calculator">30 - 6</gadget>
<output>24</output>

<gadget id="calculator">400 / 24</gadget>
<output>50/3 = around 16.666667</output>

<gadget id="calculator">(50/3) * 6</gadget>
<output>100</output>

<result>100</result>