Ma Xiaohu's home is 1,800 meters away from the school. One day, Ma Xiaohu went to school from home. After 10 minutes of departure, his father found that he had forgotten his math textbook. He immediately took the textbook and chased him. He caught up with him 200 meters away from the school. He, known that his father's speed is twice the speed of Ma Xiaohu, ask for Ma Xiaohu's speed.
马小虎的家距离学校1800米，一天马小虎从家去上学，出发10分钟后，爸爸发现他的数学课本忘记拿了，立即带上课本去追他，在距离学校200米的地方追上了他，已知爸爸的速度是马小虎速度的2倍，求马小虎的速度．
<gadget id="calculator">1_800 - 200</gadget>
<output>1_600</output>

<gadget id="calculator">1_600 / 20</gadget>
<output>80</output>

<result>80</result>