hunter takes a hound to hunt 4 kilometers away from home. After going out, the hound runs back and forth between the home and the hunter in a straight line at a speed of 150 meters per minute. It is known that the hunter's walking speed is 40 meters per minute, so when the hunter reaches the destination, how much is the total distance traveled by the hound?
一猎人带一猎犬到离家4千米的地方打猎，出门后猎犬便以每分钟150米的速度在家门和猎人之间来回直线不停奔跑．已知猎人的行走速度是每分钟40米，那么当猎人到达目的地时，猎犬奔跑的总路程是多少米？
<gadget id="calculator">4 * 1_000</gadget>
<output>4_000</output>

<gadget id="calculator">4_000 / 40</gadget>
<output>100</output>

<gadget id="calculator">100 * 150</gadget>
<output>15_000</output>

<result>15_000</result>