Tell whether each situation involves combinations or permutations. Then give the number of possible outcomes. A manager is scheduling interviews for job applicants. She has 8 time slots and 6 applicants to interview. How many different interview schedules are possible?

Answer 1

One of the main differences between a combination and a permutation is that
the order matters in a permutation.
e.g. When picking a committee of 6 people from 8 men and women, it does not matter in which order you pick them, that is, C(8,6) = 8!/(6!2!) = 8*7/2 = 28 , but...
if you were to pick a president, vice president and secretary from 5 applicants, their position makes it a permutation, that is, P(5,3) = 5!/2! = 5*4*3 = 60

In your case, it does matter how the time slots are filled with different people, you don't want applicants to show up at the wrong time, or be late, so
think of it as the 6 applicants being assigned times.
the first one can be given 8 different times,
leaving 7 different times for the 2nd applicant,
leaving 6 different times for the 3rd applicant,
....
leaving 1 time slot for the 6th applicant, so we have 8*7*6*5*4*3 = P(8,6) = 20160