Simple math problem. (Drug related)

Okay, so I got 40 2mg Klonopins for 40 bucks. (which is extremely cheap, 2mg klons go for 2-3 dollars a pop)

So, I sold 15 to a friend for 2 a piece, so he paid me 30.

I then paid 10 dollars to cover for the 40.

So, In the end I paid 10 dollars for 25 pills.

How much did each pill cost?

would it be... 25/10?

or 10/25?

Help!