The distance between A and B is 648 kilometers. A and B are walking toward each other from the two places at the same time. A travels 80 kilometers per hour, and A's speed is B's (4/5). After how many hours do they meet?
A、B两地相距648千米，甲乙两人分别从两地同时相向而行，甲每小时行80千米，甲的速度是乙的(4/5)，经过几小时两人相遇？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<gadget id="calculator">80 + 100</gadget>
<output>180</output>

<gadget id="calculator">648 / 180</gadget>
<output>18/5 = around 3.6</output>

<result>18/5 = around 3.6</result>