Over the past year, a university’s computer system has been struck by a virus at an average rate of 0.4 viruses per week. the university’s information technology managers estimate that each time a virus occurs, it costs the university $1000 to remove the virus and repair the damages it has caused. assuming a poisson distribution, what is the probability that the university will have the good fortune of being virus-free during the upcoming week? during this same week, what is the expected amount of money that the university will have to spend for virus removal and repair?