The distance between A and B is 600km. A passenger car and a truck drive towards each other from the two places one after another. The truck leaves for 2 hours first. It is known that the truck travels 50km per hour. The speed of the passenger car is 1.5 times that of the truck. How many hours after the passenger car leaves, the two cars meet?
甲、乙两地相距600km，一辆客车和一辆货车先后从两地开出相向而行，货车先开出2小时，已知货车每小时行50km．客车的速度是货车的1.5倍，客车开出几小时后两车相遇？
<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">600 - 100</gadget>
<output>500</output>

<gadget id="calculator">50 * 1.5</gadget>
<output>75</output>

<gadget id="calculator">75 + 50</gadget>
<output>125</output>

<gadget id="calculator">500 / 125</gadget>
<output>4</output>

<result>4</result>