Question

An opaque bag contains three red, two blue, and four green

marbles. What is the probability of randomly pulling out a red
marble, replacing it, then randomly drawing another red
marble?

Answer 1

• 1/9

Explanation:

Probability of drawing 1st red marble

• No. (red) / No. (total)
• 3 / (3 + 2 + 4)
• 3/9
• 1/3 - P(1)

Probability of drawing 2nd red marble

• It states it is replaced
• Number of red is same as the beginning and total number is same
• P(2) = P(1)
• 1/3 - P(2)

Probability

• P(1) x P(2)
• 1/3 x 1/3
• P = 1/9