Problem of the Week

Problem E

Such a Card

Johanna has a deck of cards with the following properties:

1. Each card in the deck has a positive three-digit integer on it.
   

2. There is exactly one card in the deck for every three-digit positive integer.
   

Johanna randomly selects a card from the deck of cards. Determine the probability that the sum of the digits of the integer on this card is 15.