The rider and the pedestrian go together from point A to point B. The rider arrives at point B 50 minutes earlier than the pedestrian, and then returns immediately. He meets the pedestrian 2 kilometers away from point B. The rider travels from point A to point B. It takes 1 hour and 40 minutes to go back and forth, how many kilometers is the distance between AB and AB? (column solution)
骑马人与小行人同进从A地前往B地，骑马人比小行人早50分钟到达B地，然后立即返回，在离B地2公里的地方与步行人相遇，骑马人从A地到B地来回一次要1小时40分钟，求AB两地间的距离是多少公里？(列式解答)
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(2/3) - (1/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 / (1/3) / 2</gadget>
<output>3</output>

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

<result>6</result>