大于等于3 为什么不是 1-（p小于等于3）而只是小于3

NO.PZ2023091601000029 问题如下 A multiple choiexhtenquestions, with five choices per question. If you neeleast three correctanswers to pass the exam, whis the probability thyou will pass simply byguessing? A.0.8% B.20.1% C.67.8% 32.2% The probability of anevent is between 0 an1. If these are mutually exclusive events, theprobability of invioccurrences are summe This probability follows abinomistribution with a p-parameter of 0.2. The probability of getting atleast three questions correis 1 – [p(0) + p (1) + p (2)] = 32.2%. 一共5个， 做对概率1/5=0.2， 不对概率4/5=0.8. 做对3题算通过， 从10题中任意选3题，根据二项分布的公式，3C10 * 0.2^3 * 0.8^7 。 请问这样算错在哪里

NO.PZ2023091601000029 问题如下 A multiple choiexhtenquestions, with five choices per question. If you neeleast three correctanswers to pass the exam, whis the probability thyou will pass simply byguessing? A.0.8% B.20.1% C.67.8% 32.2% The probability of anevent is between 0 an1. If these are mutually exclusive events, theprobability of invioccurrences are summe This probability follows abinomistribution with a p-parameter of 0.2. The probability of getting atleast three questions correis 1 – [p(0) + p (1) + p (2)] = 32.2%. 为什么不用二项分布？求解析！