Josh types the five entries in the bibliography of his term paper in random order , forgetting that thet should be in alphabetical oder by author ,What is the probability that he actually typed them in a alphabetical order?

Question

anonymous · Answer

$$\frac{1}{5!}$$

anonymous · Answer

probability first one is right is 
$$\frac{1}{5}$$ then probability second one is right given the first one is right is 
$$\frac{1}{4}$$ etc.  then multiply since they all have to be right

anonymous · Answer

a more prosaic way to think about it is that there are 5! different ways to arrange, and only one is correct.  same thing really