求翻译：无锡某校准备组织学生及学生家长到上海进行社会实践活动，为便于管理，所有人员必须乘坐同一列火车；根据报名人数，若都买一等座单程火车票需18060元，若都买二等座单程火车票且花钱最少，则需11850元；已知学生家长与教师的人数之比为2：1，无锡到上海的火车票价格（部分）如下表所示：是什么意思？

Wuxi, a school ready to organize students and parents to Shanghai social practice, for ease of management, all staff must take the same train; according to the number of applicants, to be 18,060 yuan to buy first-class seat one-way train ticket, if all bought second seat one-way train ticket and the

No-one is prepared to organize the students and the parents in Shanghai, in order to facilitate social practice activities, and all staff members must travel on the same train, and if you are buying a one way ticket, and $18,060 to buy, if you are 2, and one-way tickets and spend money, you need at