Two people, A and B, start from the same place on the ring road at the same time by bicycle, walking with their backs facing each other. Now it is known that A travels 800 meters per minute, and the time for one lap is 70 minutes. If A and B meet each other 40 minutes after departure, how many meters does B travel per minute?
甲、乙两人骑自行车从环行公路上同一地点同时出发，背向而行．现在已知甲每分钟行800米，行一圈的时间是70分钟，如果在出发后40分钟甲、乙二人相遇，那么乙每分钟行多少米？
<gadget id="calculator">800 * 70</gadget>
<output>56_000</output>

<gadget id="calculator">800 * 40</gadget>
<output>32_000</output>

<gadget id="calculator">56_000 - 32_000</gadget>
<output>24_000</output>

<gadget id="calculator">24_000 / 40</gadget>
<output>600</output>

<result>600</result>