A tourist walked up the mountain for 750 meters, which took 10 minutes, and took another 5 minutes to return by the same way. What is the average speed of one trip back and forth in meters per minute?
一位游客上山走了750米，用了10分钟，按原路返回又用了5分钟，来回一次的平均速度是每分钟多少米．
<gadget id="calculator">750 * 2</gadget>
<output>1_500</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">1_500 / 15</gadget>
<output>100</output>

<result>100</result>