Two cars start from two places at the same time and drive toward each other. It is known that car A takes 2 hours longer than car B to complete the journey. Car A travels 30 kilometers per hour and car B travels 50 kilometers per hour. How long does it take after departure? Two cars meet?
两辆汽车从两地同时出发，相向而行，已知甲车行完全程比乙车多用2小时，甲车每小时行30千米，乙车每小时行50千米，出发后多长时间两车相遇？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/30) - (1/50)</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">30 + 50</gadget>
<output>80</output>

<gadget id="calculator">2 / (1/75) / 80</gadget>
<output>15/8 = around 1.875</output>

<result>15/8 = around 1.875</result>