A Senate committee consists of 5 Republicans, 6 Democrats, and 2 Independents. A subcommittee of 3 members is randomly chosen. What is the probability that the subcommittee consists of three Democrats?
How many ways can we choose 3 members from the 13 people commitee?
How many ways can we choose 3 Democrats from the 6 Democrats?
The odds of the first pick being a Republican is 5/13. If this happens the odds of the next pick being Republican is 4/12 If that happens, the odds of the last pick being Republican is 3/11.
They all have to happen so to get the final answer, multiply all these together. (5/13)*(1/3)*(3/11) = 15/429 or about 3.5%.