Step 1: Identifying Favorable Cases
A standard deck contains 52 cards, consisting of 4 suits: hearts, diamonds, clubs, and spades, each containing 13 cards.
- Number of diamond cards = \( 13 \)
- Number of king cards = \( 4 \)
- The king of diamonds is counted twice in both sets, so we subtract 1 to avoid double counting.
Step 2: Calculating Probability
The number of favorable cases: \[ {Total diamonds} + {Total kings} - {King of diamonds} = 13 + 4 - 1 = 16. \]
Thus, the probability: \[ \frac{16}{52} = \frac{4}{13}. \]