On a 1:5,000,000 map, the length of the road from A to B is measured to be 7.5 cm, and it takes 5 hours for a car to travel from A to B. How many kilometers per hour does the car travel on average?
在一幅1：5000000的地图上，量得从甲地到乙地的公路长7.5厘米，一辆汽车从甲地到乙地用了5小时．这辆汽车平均每小时行驶多少千米？
<gadget id="calculator">1 / 5_000_000</gadget>
<output>1/5_000_000 = around 0</output>

<gadget id="calculator">7.5 / (1/5_000_000) / 100_000 / 5</gadget>
<output>75</output>

<result>75</result>