2001年的一道真题
A company takes out an insurance policy to cover accidents that occurat its manufacturing plant. The probability that one or more accidents will occur during any given month is 3/5 . The number of accidents that occur in any given month 5 is independent of the number of accidentsthat occur in all other months. Calculate the probability that there will be at least four months in which no accidents occur before the fourth month in which at least one accident occurs.
请问这道题的问题究竟该怎么理解啊,我越看越乱。。。。。。真心求助啊!!谢谢大家了!!