How much does it cost?

On the first day of college, the Dean addressed the students, pointing out some of the rules: "The female dormitory will be out-of-bounds for all male students, and the male dormitory to the female students. Anybody caught breaking this rule will be fined $20 the first time." He continued: "Anybody caught breaking this rule the second time will be fined $60. Being caught a third time will incur a hefty fine of $180. Are there any questions?" At this point, a male student in the crowd inquired:
"How much for a season pass?"

在上大学的第一天，院长向学生发表演说,说明一些规则: "女生的宿舍将会是所有的男生的禁区,男生宿舍对女生也是禁区。任何打破这一条规则的人第一次将会被罚款20美元。"他继续说: "任何人第二次被发现打破这条规则将会被罚款60美元.第三次被发现的将会招致180美元的重罚.有任何问题吗?" 此时,一位男生问: "那么进去3个月要花多少钱?