Someone walked up the mountain road from the foot of the mountain for 40 minutes, and was 200 meters away from the top of the mountain; after reaching the top of the mountain, it only took him 50 minutes to return the same way. It is known that the speed of going downhill is twice the speed of going uphill. What is his speed in meters per minute?
某人从山脚沿山路上山，走了40分钟，距山顶还有200米；他到山顶后原路返回只用了50分钟．已知下山速度是上山速度的2倍．他上山的速度是多少米/分．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) * 2</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(5/3) - (2/3)</gadget>
<output>1</output>

<gadget id="calculator">200 / 1</gadget>
<output>200</output>

<result>200</result>