- In a deck of 52 cards, there are 13 cards in each suit. The first card can be any card from the deck, so there are 52 choices for the first card.
- For the second card, to ensure it is of a different suit, there are 39 cards remaining from the other three suits.
- Hence, the probability that the two cards are of different suits is:
\[
\frac{39}{51} = \frac{39}{52 - 1} = \frac{39}{51}
\]