A and B start from the top and the foot of the mountain at the same time, and travel along the same mountain path. The uphill speed of the two is 20 m/min, and the downhill speed is 30 m/min. A returns immediately after arriving at the foot of the mountain, and B returns after resting for 30 minutes at the top of the mountain. The two meet again at a distance of 480 meters from the top of the mountain. How many meters is the mountain road long?
甲，乙二人分别从山顶和山脚同时出发，沿同一山道行进．两人的上山速度都是20米/分，下山速度都是30米/分．甲到达山脚立即返回，乙到达山顶休息30分钟后返回，两人在距山顶480米处再次相遇．山道长多少米．
<gadget id="calculator">480 / 20</gadget>
<output>24</output>

<gadget id="calculator">24 + 30</gadget>
<output>54</output>

<gadget id="calculator">54 * 30</gadget>
<output>1_620</output>

<gadget id="calculator">1_620 + 480</gadget>
<output>2_100</output>

<result>2_100</result>