There is a total of four kings in a standard deck.
There total number of 5-card combinations that is possible to draw in a 52 cards deck is given by:
The total number of ways by which we can combine three kings between four is 4!/3! = 4. Then, the total number of 5 cards combinations that includes exactly 3 kings is given by:
Therefore, the probability of being dealt three kings in five-card poker from a standard deck is given by: