Two cars depart from the same place at the same time, and deliver a batch of goods to a place 120 kilometers away. Car A arrives 20 minutes earlier than car B. When car A arrives, car B is still 15 kilometers away from the destination. How many hours did it take car A to complete the trip?
两辆汽车同时同某地出发，运送一批货物到距离120千米的地方，甲车比乙车早到20分钟，当甲车到达时，乙车还距目的地15千米．甲车行完全程用了多少小时？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">15 / (1/3)</gadget>
<output>45</output>

<gadget id="calculator">120 / 45</gadget>
<output>8/3 = around 2.666667</output>

<gadget id="calculator">(8/3) - (1/3)</gadget>
<output>7/3 = around 2.333333</output>

<result>7/3 = around 2.333333</result>