Tim has 39 pairs of headphones and 13 music players. Tim wants to sell all of the headphones and music players in identical packages.

Then Tim would put three headphones with one music player in each package.

Step-by-step explanation:

So, you'd have to divide 39 (pairs of headphones) by 13 (music players) to get three. That means that for every music player sold, he could give three headphones with it.