The distance between A and B is 600 km. A car has been driving from A to B for 3 hours, and the remaining distance is 60 km longer than the already traveled distance. What is the average speed of this car in km/h (first Draw a line segment diagram according to the meaning of the question, and then answer)
甲乙两地距离600千米，一辆汽车从甲地开往乙地，已经行了3小时，剩下的路程比已经行的多60km，这辆汽车的平均速度是多少千米/时(先根据题意画出线段图，再解答)
<gadget id="calculator">600 - 60</gadget>
<output>540</output>

<gadget id="calculator">540 / 2 / 3</gadget>
<output>90</output>

<result>90</result>