Question

In a bag, there are 8 blue marbles, 4 yellow marbles, and 6 red marbles. First question: What is the probability of not selecting a blue or yellow marble? Second question: What is the probability of first selecting a red marble, then selecting a yellow marble? Third question: What is the probability of first selecting a blue or yellow marble, replacing the marble, then selecting a red or blue marble?

Answer 1

Question 1

• P(not b or y) = P(r) = 6 / (8 + 4 + 6) = 6 / 18 = 1/3

Question 2

Assumed no replacement here

• P(r then y) = 6/18 * 4/17 = 4/51

Question 3

• P(b or y) = (8 + 4) / 18 = 12/18 = 2/3
• P(r or b) = (6 + 8)/18 = 14/18 = 7/9

• P(b or y then r or b) = 2/3*7/9 = 14/27