Question

A bag contains 6 red marbles, 6 green marbles, and 6 blue marbles. If Olivia draws a marble, replaced it and then draws another marble, what is the probability that both marbles she draws will be red?

Answer 1

1/9.

Explanation:

Prob(First marble is red) = 6/18 = 1/3

Prob(Second marble is red) = 1/3

Required probability = 1/3 * 1/3 = 1/9.

Answer 2

5/51 or 9.8

Explanation:

Since she does not put the marble back it's dependent.

1/3 chances the first marble is red and 5/17 the second is too.

Multiply and you get 5/51 odds, or approximately 9.8% chance