A and B travel from A to B. A travels 6 kilometers per hour, and B travels 8 kilometers per hour. After 1.5 hours, B returns to A and stays for half an hour. With the same original speed, how many kilometers did A travel when he was caught up?
甲、乙从A地到B地，甲每时行6千米，乙每时行8千米，1.5小时后，乙返回A地并停留半小时．原速不变，甲被追上时行了多少千米？
<gadget id="calculator">12 + 12</gadget>
<output>24</output>

<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">12 * 6</gadget>
<output>72</output>

<result>72</result>