An office has 6 employees; there are 5 female employees and 1 male employee. In how many ways can a 3 person committee be created if the committee must include the male employee?

Respuesta :

bobeld
We can approach this as how many 2 person female committees can we make that we can add the male to.

5 C 2  (combinations of 5 taken 2 at a time order doesn't matter)

5 x 4  = 20  = 10 ways.     Since the male can join any of the groups there are 
2 x 1      2                         still 10 ways.

Here's another way of looking at it.  Let's call the five females A, B, C, D and E

Here are the pairings:
AB       BC     CD     DE
AC       BD     CE
AD       BE     
AE                                       The male can be the 3rd person in any group.  Once 
                                            again, there are 10 ways to do this.