Cars A and B leave from A and B, which are 600 kilometers apart, at the same time. After 4 hours, the two cars have driven 80% of the whole journey. Given that the speed ratio of cars A and B is 5:7, how many kilometers does car A travel per hour?
甲、乙两车同时从相距600千米的A，B两地相对开出，4小时后，两车共行驶了全程的80%．已知甲、乙两车的速度比是5：7，甲车每小时行驶多少千米？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / 4</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">600 * (1/5) * (5/12)</gadget>
<output>50</output>

<result>50</result>