Cars A and B start from two cities 300 kilometers apart at the same time and drive toward each other. A's speed is 70 km/h, B's speed is 80 km/h, how many hours have passed before the two meet?
甲、乙两车同时从相距300千米的两个城市出发，相向而行．甲的速度是70千米/时，乙的速度是80千米/时，经过多少小时两人相遇？
<gadget id="calculator">70 + 80</gadget>
<output>150</output>

<gadget id="calculator">300 / 150</gadget>
<output>2</output>

<result>2</result>