Discussion Problems of the Day (14-06-11)

Posted by varsha on Jun 14, 2011; 6:14am
URL: http://discussion-forum.276.s1.nabble.com/Discussion-Problems-of-the-Day-14-06-11-tp6472885.html

Suppose that a school band consists of 10 students from the freshman class, 20 students from the sophomore class, 3o students from junior class and 40 students from senior class.If 15 students are selected at random from the band, what is the probability that at least one student will be selected from each of the four classes ?