Two people, A and B, start from A to B at the same time. A walks 80 meters per minute, and B walks 60 meters per minute. After A arrives at B, he rests for half an hour, and then returns to A. After A leaves B for 15 minutes, he meets B who is walking towards B. What is the distance between A and B?
甲、乙两人同时从A地出发前往B地，甲每分钟走80米，乙每分钟走60米．甲到达B地后，休息了半个小时，然后返回A地，甲离开B地15分钟后与正向B地行走的乙相遇．A、B两地相距多少米．
<gadget id="calculator">80 + 60</gadget>
<output>140</output>

<gadget id="calculator">140 * 15</gadget>
<output>2_100</output>

<gadget id="calculator">60 * 30</gadget>
<output>1_800</output>

<gadget id="calculator">2_100 + 1_800</gadget>
<output>3_900</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">3_900 / 1</gadget>
<output>3_900</output>

<gadget id="calculator">3_900 * 4</gadget>
<output>15_600</output>

<result>15_600</result>