Concept:
A standard deck of playing cards contains:
\[
52 \text{ cards}
\]
These cards are divided into 4 suits:
\[
\text{Hearts},\ \text{Diamonds},\ \text{Spades},\ \text{Clubs}
\]
Each suit contains:
\[
13 \text{ cards}
\]
Important facts:
• Hearts and Diamonds are red suits.
• Spades and Clubs are black suits.
• Each suit contains exactly one King.
Step 1: Determine total possible outcomes.
One card is selected from 52 cards.
Therefore:
\[
n(S) = 52
\]
Step 2: Identify favorable outcomes.
We need a red coloured king.
Red suits are:
\[
\text{Hearts and Diamonds}
\]
So favorable cards are:
• King of Hearts
• King of Diamonds
Hence:
\[
n(E) = 2
\]
Step 3: Apply probability formula.
\[
P(E) = \frac{n(E)}{n(S)}
\]
Substitute values:
\[
P(E) = \frac{2}{52}
\]
Step 4: Simplify the fraction.
Divide numerator and denominator by 2:
\[
P(E) = \frac{1}{26}
\]
Step 5: Verification and understanding.
There are:
\[
4 \text{ kings total}
\]
Among them:
\[
2 \text{ are red}, \quad 2 \text{ are black}
\]
Thus probability of selecting a red king from the full deck is:
\[
\frac{2}{52} = \frac{1}{26}
\]
Final Answer:
\[
\boxed{\frac{1}{26}}
\]