Two trains depart from two places 540 kilometers apart at the same time, and run towards each other. Car A travels 75 kilometers per hour, and train B travels the distance of A train (4/5) per hour. How long does it take for the two trains to meet?
两列火车同时从相距540千米的两地出发，相对而行，甲车每小时行75千米，乙车每小时行的路程是甲车的(4/5)，几小时两车相遇？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">75 * (4/5)</gadget>
<output>60</output>

<gadget id="calculator">75 + 60</gadget>
<output>135</output>

<gadget id="calculator">540 / 135</gadget>
<output>4</output>

<result>4</result>