1. Them are 5 bags, of which 3 are empty and 2 contain a ball. If a ball is randomly placed into a bag, and then a bag is randomly selected, the probability that the bag is empty is( ).
文摘1. Them are 5 bags, of which 3 are empty and 2 contain a ball. If a ball is randomly placed into a bag, and then a bag is randomly selected, the probability that the bag is empty is( ).