There are 3 people, A, B, and C. A walks 40 meters per minute, and C walks 60 meters per minute. A and B start from A and B at the same time and walk towards each other. After they set off for 15 minutes, C starts from B. Go after B. A and B met on the way first, A met C again after 7 minutes, and C caught up with B after another 63 minutes, how many kilometers are the distance between A and B?
现有甲、乙、丙3人，甲每分钟走40米，丙每分钟走60米，甲、乙从A、B两地同时出发相向而行，他们出发15分钟后，丙从B地出发去追赶乙．甲、乙先在途中相遇，7分钟后甲又与丙相遇，又过63分钟丙才追上乙，求A、B两地相距多少千米？
<gadget id="calculator">7 + 63</gadget>
<output>70</output>

<gadget id="calculator">60 * 70</gadget>
<output>4_200</output>

<gadget id="calculator">60 + 40</gadget>
<output>100</output>

<gadget id="calculator">7 * 100</gadget>
<output>700</output>

<gadget id="calculator">4_200 - 700</gadget>
<output>3_500</output>

<gadget id="calculator">3_500 / 70</gadget>
<output>50</output>

<gadget id="calculator">40 + 50</gadget>
<output>90</output>

<gadget id="calculator">60 * 15</gadget>
<output>900</output>

<gadget id="calculator">40 * 7</gadget>
<output>280</output>

<gadget id="calculator">60 * 7</gadget>
<output>420</output>

<gadget id="calculator">900 - 280 - 420</gadget>
<output>200</output>

<gadget id="calculator">60 - 40 - 50</gadget>
<output>-30</output>

<gadget id="calculator">40 + (-30)</gadget>
<output>10</output>

<gadget id="calculator">200 / 10</gadget>
<output>20</output>

<gadget id="calculator">90 * 20</gadget>
<output>1_800</output>

<result>1_800</result>