设计一个可以模拟渡船等待时间的系统。具体描述为有客车和货车需要乘坐渡船，一班渡船10分钟，可以上10辆车，并且规定每上4辆客车可以上1辆货车，若客车不足则以货车代替。要求对这一情景进行模拟，计算出客车和货车的平均等待时间。-Ferries designed to simulate a system latency. Specifically described as having buses and trucks need to take the ferry, ferry 10 minutes