Cars A and B respectively drive from A. Two places B set off at the same time, and meet for the first time 20 kilometers to the right of the midpoint of the two places 4 hours after departure. It is known that the speed of car A is 50 kilometers per hour, how many kilometers are there between A and B?
甲、乙两车分别从A．B两地同时出发，出发4小时后在距离两地中点右边20千米处首次相遇，已知甲车的速度为每小时50千米，求A、B两地相距多少千米？
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 * (1/2)</gadget>
<output>10</output>

<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">50 + 40</gadget>
<output>90</output>

<gadget id="calculator">90 * 4</gadget>
<output>360</output>

<result>360</result>