Xiao Ming went to climb the mountain. It took 18 minutes to walk 720 meters up the mountain, and only 15 minutes to return by the same road. How much faster is the speed of going downhill than going uphill?
小明去登山，上山时走了720米用了18分钟，按原路返回只用了15分钟．下山的速度比上山快多少米/分？
<gadget id="calculator">720 / 15</gadget>
<output>48</output>

<gadget id="calculator">720 / 18</gadget>
<output>40</output>

<gadget id="calculator">48 - 40</gadget>
<output>8</output>

<result>8</result>