Question

a local library shows movies on Thursday evening.the library administrator has chosen the next 6 movies he will show , but he has not decided in which order to show them. how many possible orderings of the six movie are there?

Answer 1

For the first movie he has 6 choices, then for the second since he has chosen the first there are only 5 left, then for the third there are only 4 choices left and so on.

Therefore the answer is 6!=6*5*4*3*2=720 orderings

Answer 2

So,

We can see that this is a permutation.

The total number of permutations will be the number with an exclamation mark attached to it.

6! = total number of possible permutations
6! = 720

There are 720 possible permutations.