Twenty people apply for 5 job openings as teacher assistants. How many different groups of people can be hired?

15504 different groups

Step-by-step explanation:

We have a total of 20 people, and we want to know how many groups of 5 people we can make, where the order of the people inside the group doesn't matter, so we can solve this question calculating the combination of 20 choose 5.

The formula for combination is:

C (n, p) = n! / (p! * (n-p) !)

In this case, we have n = 20 and p = 5, so:

C (20, 5) = 20! / (5! * 15!) = 20*19*18*17*16 / (5*4*3*2) = 15504

So we have 15504 different groups.