Xiao Ming went to climb a mountain. It took 18 minutes to walk 720 meters up the mountain, and only 15 minutes to return the same way. How many meters per minute is the average downhill walk?
小明去爬山，上山时走720米用了18分钟，按原路返回只用了15分钟，下山平均每分钟走多少米？
<gadget id="calculator">720 / 15</gadget>
<output>48</output>

<result>48</result>