The distance between A and B is 520 kilometers. An express train departs from A and a slow train departs from B at the same time. The two trains are traveling towards each other. The express train travels 80 kilometers per hour, which is 1.6 times the speed of the slow train. How long does it take for the two cars to meet?
甲、乙两城相距520千米，一列快车从甲城出发，同时一列慢车从乙城开出，两车相向而行．快车每小时行80千米，是慢车速度的1.6倍，经过多少时间两车相遇？
<gadget id="calculator">80 / 1.6</gadget>
<output>50</output>

<gadget id="calculator">80 + 50</gadget>
<output>130</output>

<gadget id="calculator">520 / 130</gadget>
<output>4</output>

<result>4</result>