If a committee of 3 is to be chosen at random from a class o

If a committee of 3 is to be chosen at random from a class of 12 students, what is the probability of any particular committee being selected? (Enter your answer as a fraction.)
________?

What if the committee is to consist of a president, a vice president, and a treasurer? (Enter your answer as a fraction.)
________?

Solution

a) total number of selections = ¹²C₃ = 12*11*10/6 = 220

probability of any particular committee being selected = 1/220

b)total number = ¹² P₃   =   12*11*10

probability = 1/1320