Probability Question 415

Question: A bag contains 6 white, 7 red and 5 black balls. If 3 balls are drawn from the bag at random, then the probability that all of them are white is

Options:

A) $ \frac{20}{204} $

B) $ \frac{5}{204} $

C) $ \frac{1}{3} $

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  •                 3 ball can be drawn in  $ {}^{18}C_3 $  ways                    Favourable cases  $ ={}^{6}C_3 $                      
    

$ \therefore $ Required probability $ =\frac{{}^{6}C_3}{{}^{18}C_3}=\frac{6\times 5\times 4}{18\times 17\times 16}=\frac{5}{204} $ .