and B start from A and B respectively at the same time and walk toward each other. After meeting for the first time, they continue to move forward, and return immediately after reaching the starting point of the other party. The distance between the second meeting point and the first meeting point is 2.4 kilometers. If A's speed is B's (4/5), then how many kilometers is the distance between A and B?
甲、乙两人同时分别从A、B两地出发相向而行，第一次相遇后两人继续前进，到过对方的出发点后都立即返回．第二次相遇点与第一次相遇点相距2.4千米．若甲的速度是乙的(4/5)，那么A、B两地相距的路程是多少千米．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">3 * (4/9)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">3 - (4/3) - 1 - (4/9)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">2.4 / (2/9)</gadget>
<output>10.8</output>

<result>10.8</result>