The distance between A and B is 427.5 km. A passenger car and a truck drive towards each other from the two places at the same time. The bus travels 50 km per hour and the truck travels 45 km per hour. How many hours later will the two cars meet?
甲、乙两地相距427.5km，一辆客车和一辆货车分别从两地同时相向而行，客车每小时行50km，货车每小时行45km．几小时后两车相遇？
<gadget id="calculator">50 + 45</gadget>
<output>95</output>

<gadget id="calculator">427.5 / 95</gadget>
<output>4.5</output>

<result>4.5</result>