A bag contains only red, green, brown and yellow marbles. The probabilities of selecting each colour are Green is 0.1, Brown is 0.72 what is the probabilities of choosing Yellow and Red if they are the same value?

Answer 1

probability of choosing other than green or brown
= 1 -.1 - .72 = .18
so .18 * .18 if there are LOTs of marbles in there so the probability does not change when you remove one.