Question : A box contains 2 black, 4 white and 3 red balls. One ball is drawn at random from the box and kept aside. From the remaining balls in the box, another ball is drawn at random and kept aside the first. This process is repeated till all the balls are drawn from the box. The probability that the balls drawn are in the sequence of 2 black, 4 white and 3 red is
(A) 1/1260
(B) 1/7560
(C) 1/126
(D) none of these
Answer : option (A)
Solution :
The required probability is
\dfrac{2}{9}\times \dfrac{1}{8}\times \dfrac{4}{7}\times \dfrac{3}{6}\times \dfrac{2}{5}\times \dfrac{1}{4}\times 1\times 1\times 1=\dfrac{1}{1260}