A bag contains

Question

4
white marbles,
5
red marbles, and
9
blue marbles.

If a marble is drawn from the bag, replaced, and another marble is drawn, what is the probability of drawing first a white marble, and then a blue marble?
A bag contains
5
green marbles,
9
blue marbles, and
4
red marbles.

If two different marbles are drawn from the bag, what is the probability of drawing first a green marble and then a red marble?

Answer 1

1.
prob(white, then blue) = (4/18)(9/18) = 1/9 , with the first marble returned.

2. assuming the first marble is not returned
prob(green, then red) = (5/18)(4/17) = 10/153