A and B walk towards each other from A and B at the same time, and meet at C after 3 hours; if A travels 1 km more per hour and B starts 0.5 hours earlier than A, they will still be at C Meet; if B travels 1 km less per hour, and A starts 0.5 hours later than B, the two will also meet at C. What is the distance in miles between A and B?
甲、乙二人同时从A、B两地相向而行，经过了3小时在C地相遇；如果甲每小时多走1千米，乙比甲提前0.5小时出发，二人还会在C地相遇；如果乙每小时少走1千米，甲比乙晚出发0.5小时，二人也会在C地相遇．A、B两地间路程是多少千米．
<gadget id="calculator">2.5 / 0.5</gadget>
<output>5</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">3.5 + 3.5</gadget>
<output>7</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">15 + 21</gadget>
<output>36</output>

<result>36</result>