Question

Two cards are drawn at random and without replacement from a pack of 52 playing cards. Find the probability that both the cards are black.

Let $P\left( A \right)$ be the probability of getting a black card in the first draw.
$\therefore P\left( A \right) = \dfrac{{26}}{{52}} = \dfrac{1}{2}$
Let $P\left( B \right)$ be the probability of getting a lack card in the second draw.
Then, $P\left( B \right) = \dfrac{{25}}{{51}}$
$= P\left( A \right) \times P\left( B \right) \\ = \dfrac{1}{2} \times \dfrac{{25}}{{51}} = \dfrac{{25}}{{102}} \\ = 0.2451 \\$