Answer
$\frac{2}{13}$
Work Step by Step
We know that $probability=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}$
The total number of cards (the number of all outcomes) is $52$
There are $2$ cards that are either king or ace in each suit and we have $4$ suits, thus there are $4\cdot2=8$ "good outcomes".
Hence the probability here is: $\frac{8}{52}=\frac{2}{13}$
