Only two moving companies, United and North American, provide local delivery service in a small western city. United operates 20 percent of the trucks, North American the remaining 80 percent. On a dark and rainy night, a pedestrian is run over and killed by a moving van. The lone witness to the incident testifies that the van was owned by United. An independent laboratory hired by the court finds that under dark and rainy conditions, the witness is able to identify the owner of a moving van with 90 percent accuracy. What is the probability that the van that struck the witness was owned by United?