Xiaojun's home is 900 meters away from the school. It took Xiaojun 10 minutes to go to school and 8 minutes to leave school. What is the average speed of Xiaojun going to school and leaving school?
小军家里距离学校900米，小军上学用了10分钟，放学用了8分钟，问小军上学和放学平均速度是多少？
<gadget id="calculator">900 * 2</gadget>
<output>1_800</output>

<gadget id="calculator">10 + 8</gadget>
<output>18</output>

<gadget id="calculator">1_800 / 18</gadget>
<output>100</output>

<result>100</result>