Someone walks along the mountain road from the bottom of the mountain for 1 hour, and the distance from the top of the mountain is still 1,000 meters away; but it takes 50 minutes to walk from the top of the mountain to the bottom of the mountain. It is known that the speed of going down the mountain is twice the speed of going up the mountain. What is the length of this mountain road in meters?
某人从山下沿山路走了1小时，距山顶还差1000米；而从山顶到山下50分钟就可以走完．已知下山速度是上山速度的2倍，这条山路长多少米．
<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<gadget id="calculator">1_000 / 40</gadget>
<output>25</output>

<gadget id="calculator">25 * 60</gadget>
<output>1_500</output>

<gadget id="calculator">1_500 + 1_000</gadget>
<output>2_500</output>

<result>2_500</result>