Two hunters A and B walk towards each other at the same time from two places 900 meters apart. A walks 100 meters per minute, and B walks 80 meters per minute. A's hunting dog runs 500 meters per minute. It starts at the same time as A and goes to B. When it reaches B, it immediately turns back to A. It runs back and forth in this way until A and B meet. How many meters has the hound run in total?
甲、乙两个猎人同时从相距900米的两地相向而行，甲每分钟行走100米，乙每分钟行走80米．甲的猎狗每分钟跑500米，与甲同时起步便前往乙处，到了乙处又立马回头到甲处，这样来回跑，直到甲乙相遇为止时，猎狗共跑了多少米？
<gadget id="calculator">100 + 80</gadget>
<output>180</output>

<gadget id="calculator">900 / 180</gadget>
<output>5</output>

<gadget id="calculator">500 * 5</gadget>
<output>2_500</output>

<result>2_500</result>