A, B, and C are three people. A’s speed is 5.4 km/h, B’s speed is 4.5 km/h, and C’s speed is 3.6 km/h. If A travels from city A, B and C travel from city B , three people set off at the same time and walk towards each other. After A and B met, they met C again after 4 minutes. So how many kilometers is the distance between A and B?
甲、乙、丙三人，甲的速度是5.4千米/小时，乙的速度是4.5千米/小时，丙的速度是3.6千米/小时，如果甲从A城，乙和丙从B城，三人同时出发相向而行，甲和乙相遇后，过了4分钟又与丙相遇，那么A、B两城间的距离是多少千米？
<gadget id="calculator">5.4 + 3.6</gadget>
<output>9</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">4.5 - 3.6</gadget>
<output>0.9</output>

<gadget id="calculator">(1/15) / 0.9</gadget>
<output>0.074074</output>

<gadget id="calculator">5.4 + 4.5</gadget>
<output>9.9</output>

<gadget id="calculator">9 * 0.074074 * 9.9</gadget>
<output>6.599993</output>

<result>6.599993</result>