and B go back and forth between AB and AB, which are 2000 meters apart. A starts from A first, and B also starts from A after 9 minutes, and catches up with A at C, which is 1200 meters away from A. When B arrives at B, he immediately keeps the same speed. Return to point A, A goes to point B to rest for 1 minute, then speeds up and returns to point A, and catches up with point B at point C, ask how many minutes before A arrives at point A before B?
甲乙往返于相距2000米的AB两地，甲先从A地出发，9分钟后乙也从A地出发，并在距A地1200米的C地追上甲，乙到B地后立即原速向A地返回，甲到B地休息1分钟后加快速度向A地返回，并在C地追上乙，问甲比乙提前多少分钟到A地？
<gadget id="calculator">2_000 - 1_200</gadget>
<output>800</output>

<gadget id="calculator">800 / 1_200</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">9 * (2/3)</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">1_200 / 800</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">7 * (3/2)</gadget>
<output>21/2 = around 10.5</output>

<result>21/2 = around 10.5</result>