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A urn contains 3 red and 4 green marbles. If three marbles are picked at random, what is the probability that two are green and one is red?

A) 3 / 7
B) 18 / 35
C) 5 / 14
D) 4 / 21

Correct Answer:


B) 18 / 35

Description for Correct answer:
Number of ways to select 3 marbles out of 7 marbles = n(S) =7C3 = 35
Probability that 2 are green and 1 is red n(E) = \( 4C_2 \times 3C_1 \)= 18

Required probability = 18 / 35

Part of solved Probability questions and answers : >> Aptitude >> Probability

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