A bag contains 7 blue marbles, 12 green marbles, and 5 red marbles. Two marbles are drawn one at a time. What is the probability that the second marble is blue, given the first marble was green and was replaced?
add all of the marbles and that will be your denominator. the number of marbles in the color you choose, in this case blue, goes in the numerator. that's how you get the ratio of 5:24
