A jar contains 10 marbles consisting of an equal number of red, green, and blue marbles. Three marbles are removed from the jar and discarded. What is the probability that only two colors will remain in the jar after the Three marbles have been removed?
Answers.
A) 1/40  B) 1/165  C) 1/81  D) 1/30  E) 1/20
Jar contains {3-red, 3-green, 3-blue} marbles. We are asked to find the probability that after removing 3 marbles only 2 colours remain in the jar, i.e., the probability of removing EITHER red, OR green, OR blue.   Sample space = 10C3 = 120.   Probability of choosing 3 red = 3C3/10C3 = 1/120.   Probability of choosing 3 green = 3C3/10C3 = 1/120.   Probability of choosing 3 blue = 3C3/10C3 = 1/120.   Required probability = 1+1+1/120 = 3/120 = 1/40. 1/40ns (1/40).
<result>A</result>
A jar contains 10 marbles consisting of an equal number of red, green, and blue marbles. Three marbles are removed from the jar and discarded. What is the probability that only two colors will remain in the jar after the Three marbles have been removed?