Answer
$\frac{1}{575,757}$
Work Step by Step
Because the order is not important, we can use the combination rule to determine the number of possibilities: $\frac{39!}{(39-5)!5!}=575,757$.
We also know that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$, therefore $P(success)=\frac{1}{575,757}$.