P(NOT blue) = 1 - P(blue) = 1 - 1/4 = 3/4. Answer:Step-by-step explanation:We have been given that a bag contains 8 red marbles 3 blue marbles and 1 green marble. We are asked to find the probability of not getting a blue marble.Probability of not getting a blue marble will be equal to probability of getting red marble plus probability of getting green marble.Therefore, the probability of not getting a blue marble is .