Two cards are a blackjack if one is an A and the other is KQ

Two cards are a blackjack if one is an A and the other is K,Q,J, or 10.

(a) If you pick two cards out of a deck, whats the probability that you will get a blackjack?

Solution

a)

There are 4 ways to get an A, and 16 ways to get a K, Q, J, or 10.

Thus, there are 4*16 = 64 ways.

Now, there are 52C2 ways to pick any 2 cards.

Thus,

P(blackjack) = 64 / (52C2) = 0.04826546 [answer]