On a map with a scale of 1:4000000, it is known that the distance on the map between the two cities A and B is 10.5cm. Cars A and B of the two cities of A and B leave at the same time and drive towards each other. Car travels 40km per hour, and car B travels 35km per hour. How many hours later will the two cars meet?
在一幅比例尺是1：4000000的地图上，已知A、B两城间的图上距离为10.5cm，A、B两城的甲车、乙车同时开出，相向而行，甲车每小时行40km，乙车每小时行35km．几小时后两车相遇？
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">40 + 35</gadget>
<output>75</output>

<gadget id="calculator">10.5 / (1/4_000_000) / 100_000 / 75</gadget>
<output>5.6</output>

<result>5.6</result>