Answer: You have a better chance if you do not replace the red marble.
Step-by-step explanation:
The bag has:
5 red marbles
8 blue marbles
4 yellow marbles
3 green marbles
A total of 5 + 8 + 4 + 3 = 20
You want to draw a red marble and then a blue marble.
The probability of drawing a red marble in your first attempt is the number of red marbles divided the total number of marbles:
P1 = 5/20
now you want to draw a blue marble.
If you replace the red marble, you have 20 marbles again in the bag, then the probability of drawing a blue marble is:
P2 = 8/20
The joint probability is P = P1*P2 = (5/20)*(8/20) = 0.1
If you do not replace the red marble, you have 19 total marbles in the bag, then the probability of taking a blue marble is:
P2 = 8/19
The joint probability is:
P = P1*P2 = (5/20)*(8/19) = 0.105
The probability is slightly bigger if you do not replace the red marble.
