Car A travels 40 kilometers per hour, and car B travels 60 kilometers per hour. Car A starts from point A and car B starts from point B at the same time and travels towards each other. 4.5 hours after the two cars meet, car A arrives at point B. How many kilometers are there between A and B?
甲车每小时行40千米，乙车每小时行60千米，甲车从A地，乙车从B地同时出发相向而行．两车相遇后4.5小时，甲车到达B地．A、B两地相距多少千米？
<gadget id="calculator">40 + 60</gadget>
<output>100</output>

<gadget id="calculator">4.5 / 60</gadget>
<output>0.075</output>

<gadget id="calculator">40 * 0.075</gadget>
<output>3</output>

<gadget id="calculator">100 * 3</gadget>
<output>300</output>

<result>300</result>