Question

Two cards are drawn successively with replacement from a well shuffled pack of 52 cards. Find the probability distribution of the number of kings.

Answer 1

Let X denote the number of kings in a sample of 2 cards drawn from a well-shuffled pack of 52 playing cards. Then, X can take the values 0, 1 and 2.
Now,
$$\begin{gathered} P\left(X=0\right) \\ =P\left(\mathrm{no}\mathrm{kings}\right) \\ =\frac{48}{52}\times \frac{48}{52} \\ =\frac{12\times 12}{13\times 13} \\ =\frac{144}{169} \\ P\left(X=1\right) \\ =P\left(1\mathrm{king}\right) \\ =\frac{4}{52}\times \frac{48}{52} \\ =\frac{2\times 12}{13\times 13} \\ =\frac{24}{169} \\ P\left(X=2\right) \\ =P\left(2\mathrm{kings}\right) \\ =\frac{4}{52}\times \frac{4}{52} \\ =\frac{1\times 1}{13\times 13} \\ =\frac{1}{169} \end{gathered}$$

Thus, the probability distribution of X is given by

X	P(X)
0	$\frac{144}{169}$
1	$\frac{24}{169}$
2	$\frac{1}{169}$