The distance between AB and AB is 180 kilometers. Cars A and B drive from the two places at the same time and travel in the same direction. Car A travels 105 kilometers per hour, and car B travels 81 kilometers per hour. After how many hours can car A catch up with car B?
AB两地相距180千米，甲乙两车同时从两地开出，同向而行．甲车每小时行105千米，乙车每小时行81千米，几小时后甲车能追上乙车？
<gadget id="calculator">105 - 81</gadget>
<output>24</output>

<gadget id="calculator">180 / 24</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>