A passenger car and a truck drive towards each other at the same time from two places 630 kilometers apart. It is known that the speed of the truck is 80 kilometers per hour, and the speed ratio of the passenger car and the truck is 5:4. How many hours will it take for the two cars to meet?
客车和货车同时从相距630千米的两地相向开车，已知货车的速度是每小时80千米，客车和货车的速度比是5：4，经过多少小时后两车相遇？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

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

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

<gadget id="calculator">630 / 180</gadget>
<output>7/2 = around 3.5</output>

<result>7/2 = around 3.5</result>