In a mountain climbing competition, Chen Ming walked up the mountain at 45 meters per minute and reached the top of the mountain in 20 minutes. Then go back along the same road and reach the foot of the mountain in 18 minutes. How many meters per minute did Chen Ming walk down the mountain?
在一次登山比赛中，陈明上山每分钟走45米，20分钟到达山顶．然后沿原路返回，18分钟到达山脚．陈明下山时每分钟走多少米？
<gadget id="calculator">20 / 18</gadget>
<output>10/9 = around 1.111111</output>

<gadget id="calculator">45 * (10/9)</gadget>
<output>50</output>

<result>50</result>