You are dealt one card from a 52 card deck find the probability you are dealt an ace or a black card?

There are 26 black cards.  There are 4 aces, but the two black ones were already counted, so we don't want to count them again.  Thus, there are 26 black cards and 2 red aces, which make 28 cards that we could pull to get "an ace or a black card."  There are 52 cards in a standard deck.  Thus, the probability is:

28/52

This simplifies to:

7/13