Question

A bag contains $9$ marbles, $3$ of which are red, $3$ of which are blue, and $3$ of which are yellow. If three marbles are selected from the bag at random, what is probability that they are all of different colors?

• A. $\frac{1}{15}$
• B. $\frac{9}{28}$
• C. $\frac{1}{19}$
• D. $\frac{1}{20}$

Answer 1

Answer: (B)

$\frac{9}{28}$

Total number of marbles=9

Number of red marbles=3

Number of blue marbles=3

Number of yellow marbles=3

Three marbles are selected from the bag at random probability that they are all of different colours=$\frac{{}^3{C}_1{\ast }^3{C_1}^3{C}_1}{{}^9{C}_3}=\frac{9}{28}$