A bag contains 5 red marbles and 3 blue marbles. What is the probability of drawing a red marble, keeping it, and then drawing another red marble?

Answer 1

total Amount of Marbles in the bag is:

5 + 3 = 8

So, since there are 5 Red marbles, the probability of drawing one is 5 / 8.

Now that you pulled that marble out, you have 7 marbles total left in the bag, 4 of those are read (5 originally, minus the one you took out.

So, the probability of the second round is 4/7.

To find the overall probability, you multiply those probabilities together:

4/7*5/8 = 20/56

Which reduces to 10/28 = 5/14

Answer 2

For this problem you are going to need to multiply 2 probabilities together: P(#1 is red) * P(#2 is red). To find the probability of the first marble being red, you need to divide the number of red marbles by the total number of marbles to get 5/8. For the 2nd probability, you need to keep in mind that you have already drawn one red marble - this means that there are only 4 red marbles left and 7 total marbles left so the 2nd probability is 4/7. When you multiply these probabilities together you will get your answer.