Problema Solution
A bag contains 5 blue marbles, 6 red marbles, and 9 green marbles. Two marbles are drawn at random, one at a time. What is the probability of selecting a green marble and then, without replacing it, a red marble?
Answer provided by our tutors
P(green) = 9/(5 + 6 + 9) = 9/20
P(red, after a green has been drawn) = 6/(20 - 1) = 6/19
P(green and then, without replacing it, a red marble) = P(green)*P(red after a green has been drawn)
P(green and then, without replacing it, a red marble) = (9/20)(6/19)
P(green and then, without replacing it, a red marble) = 0.1421