Cars A and B set off from A and B respectively at the same time, travel towards each other, and return immediately after arriving at the opposite station. For the first time, A meets B at a distance of 1.5 kilometers from the midpoint, and the second time, at a distance of 3 kilometers from point A. Meet B at a kilometer. So what is the distance between A and B?
甲、乙两车分别从A、B两地同时出发，相向而行，到达对方车站后立即返回，第一次甲在过中点1.5千米处与乙相遇，第二次在距离A点3千米处与乙相遇．那么A、B两地相距多少？
<gadget id="calculator">1.5 * 3</gadget>
<output>4.5</output>

<gadget id="calculator">3 + 4.5</gadget>
<output>7.5</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 3</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">2 - (3/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">7.5 / (1/2)</gadget>
<output>15</output>

<result>15</result>