I'm Stuck with this question. It is exercise no. 3.30 from the book "Probability & Statistics for Computer Scientists" :
Eric from Exercise 3.29 continues driving. After three years, he still has no traﬃc accidents. Now, what is the conditional probability that he is a high-risk driver?
And Exercise 3.29 is:
An insurance company divides its customers into 2 groups. Twenty percent of customers are in the high-risk group, and eighty percent are in the low-risk group. The high-risk customers make an average of 1 accident per year while the low-risk customers make an average of 0.1 accidents per year. Eric had no accidents last year. What is the probability that he is a high-risk driver?
I have successfully solved 3.29 by Poisson Distribution and got the answer 0.09225. But I can't figure out how to do 3.30 and what to do with that "After three years" phrase... Please Explain like I'm 5.