There are 15 articles in a box, 5 of which are colored. If 5 articles are selected at random, what is the probability that one of the articles is not colored?
"one of the articles is not colored" means 1 non-colored and 4 colored (e.g. NCCCC).
ways of selecting 5 articles = 15!/(10!*5!) = 3003
ways of selecting one non-colored = 10
ways of selecting 4 colored = 5
prob = 5*10/3003 = 50/3003
















