A box contains two white, three black and four red balls. The number of ways of selecting 3 balls from the box with atleast one black ball is

Step-by-step solution

Number of ways of selecting 3 balls out of 9 balls without any restriction is 9 C 3 . Number of ways of selecting 3 balls such that no black ball is selected is 6 C 3 . Number of ways such that atleast one black ball is selected is C 9 3 − C 6 3 = 84 − 20 = 64