Answer
The probability is $\frac{2}{13}$.
Work Step by Step
We know that there are fifty-two outcomes in a $52$ card deck, so $\text{n}\left( \text{S} \right)=\text{ 52}$.
There are four outcomes when the pulled card is an ace, so $\text{n}{{\left( \text{E} \right)}_{\text{an ace}}}=\text{ 4}$.
The probability of getting an ace is given below
$\text{P}{{\left( \text{E} \right)}_{\text{an ace}}}\text{ = }\frac{\text{n}{{\left( \text{E} \right)}_{\text{an ace}}}}{\text{n}\left( \text{S} \right)}\text{ = }\frac{4}{52}\text{ = }\frac{1}{13}$.
And there are four outcomes when the pulled card is a king, so $\text{n}{{\left( \text{E} \right)}_{\text{a king}}}=\text{ 4}$.
The probability of getting a king is given below
$\text{P}{{\left( \text{E} \right)}_{\text{a king}}}\text{ = }\frac{\text{n}{{\left( \text{E} \right)}_{\text{a king}}}}{\text{n}\left( \text{S} \right)}\text{ = }\frac{4}{52}\text{ = }\frac{1}{13}$.
Thus, the probability of getting an ace or a king is
$\begin{align}
& {{\text{P}}_{\text{an ace or a king}}}\text{ = }{{\text{P}}_{\text{an ace}}}+\text{ }{{\text{P}}_{\text{a king}}} \\
& =\text{ }\frac{1}{13}\text{ }+\text{ }\frac{1}{13} \\
& =\text{ }\frac{2}{13}
\end{align}$
