Two people, A and B, go on a mountain-climbing trip. They start climbing from the foot of the mountain at the same time, and descend immediately after reaching the top of the mountain. Both descend at twice the speed of going up the mountain. , B has just walked down the mountain (1/2), what is the distance from the foot of the mountain to the top of the mountain in meters
甲、乙两人登山旅游，二人同时从山脚出发开始爬山，到达山顶后立即下山，二人下山速度都是上山的2倍，甲到达山顶时，乙离山顶400米，甲回到山脚时，乙下山刚走完(1/2)，则山脚到山顶的距离为多少米
<gadget id="calculator">400 * 6</gadget>
<output>2_400</output>

<result>2_400</result>