Matt, Bob, Amy, and John are waiting in line at a fast food restaurant. How many different ways can they line up to place their order

Answer 1

1st spot can be filled in 4 ways
(Matt, Bob, Amy or John)

2nd spot can be filled in 3 ways
(since 1st spot is now filled by one of the 4)

3rd spot will be filled in 2 ways

4rd spot will be filled in 1 way since the rest all spots are taken

Total # of ways = 4 x 3 x 2 x 1

24 ways answer