Guided Example #2 - Factorials, Combination, Permutation

In a company there are seven executives: four women and three men. Three are selected to attend a seminar. Find the probability that one man and two women will be selected.

A. 335     B. 635     C. 1835     D. 1235

 

 

Step 1

Let's start by finding the sample space. There are seven people and we are picking 3 of them.
This can be done in
C73=7!(3!)(4!)=35 ways.

Step 2

There are 3 ways to pick one man out of 3(C31=3) and 6 ways (C42=6) to pick 2 women out of 4.
So the desired probability is
P=C31C42C73=(3)(6)35=1835.

All Steps

Let's start by finding the sample space. There are seven people and we are picking 3 of them.
This can be done in
C73=7!(3!)(4!)=35 ways.

There are 3 ways to pick one man out of 3(C31=3) and 6 ways (C42=6) to pick 2 women out of 4.
So the desired probability is
P=C31C42C73=(3)(6)35=1835.