Step 1: Know the basic facts needed to compute probabilities concerning cards

There are a total of 52 cards in a standard deck of cards.

There are 4 suit - diamonds (♦), spades (♠), hearts (♥) and clubs (♣)

Know more: https://en.wikipedia.org/wiki/Standard_52-card_deck

So, total number of out comes = 52

Step 2: Determine the favorable outcomes

Total 52 cards in a deck. Out of these, half the cards i.e. 26 cards are red

and remaining cards are black. Also, there are 4 suits.

So, there are 13 cards of each suits ( \because \frac{52}{4} = 13)

Each suit has one King card.

So, there are 2 kings in red- one of hearts and the other of diamonds.

Thus, favorable outcomes = 2

Step 3: Calculate the probability of selecting a red king from a deck of card

The probability of selecting a red king from a deck of card = \frac{Favorable\ outcomes}{Total\ number\ of\ outcomes}

= \frac{2}{52}

= \frac{1}{26}