Posted by Amanda on .
A law firm has thirteen senior and nine junior partners. A committee of 6 partners is selected at random to represent the firm at a conference. What is the probability that at least one of the junior partners is on the committee?

Finite Math 
Reiny,
Looks like you want us to do an assignment for you.
I will do this last one, but then you must show us that you have some kind of method for doing these.
number of possible committees
= C(22,6) = 74613
number with NO junior partners = C(13,6) = 1716
so the number with at least one junior = 746131716 = 72897
prob of at least one junior = 72897/74613 = 6627/6783= 2209/2261 = appr .977 
Finite Math 
Amanda,
i want help understanding how to solve the problems, not just the answers. I understand how to get the denominator, by getting the total and nCr the sample, but i cannot figure out the numerator when it comes to solving these probability problems.