A and B are 6 kilometers apart. Chen Yu walks from place A to place B, walking 80 meters per minute for the first half of the time, and 70 meters per minute for the second half of the time. In this way, how many meters did he walk more in the first half of the time than in the second half of the time.
甲乙两地相距6千米．陈宇从甲地步行去乙地，前一半时间每分钟走80米，后一半的时间每分钟走70米．这样他在前一半的时间比后一半的时间多走多少米．
<gadget id="calculator">80 - 70</gadget>
<output>10</output>

<gadget id="calculator">0.07 + 0.08</gadget>
<output>0.15</output>

<gadget id="calculator">6 / 0.15</gadget>
<output>40</output>

<gadget id="calculator">10 * 40</gadget>
<output>400</output>

<result>400</result>