http://www.ck12.org Chapter 2. Conditional Probability
P(first club) =13
52
P(second club) =12
51
P(club and club) =13
52
×
12
51
P(club and club) =156
2 , 652
P(club and club) =1
17
Step 2:Calculate the probability of choosing a club as the second card when a club is chosen as the first card.
Probability of drawing the second club=
P(club and club)
P(first club)P(club|club) =1
17
13
52
P(club|club) =1
17
×
52
13
P(club|club) =52
221
P(club|club) =4
17
Step 3:Write your conclusion.
Therefore, the probability of selecting a club as the second card when a club is chosen as the first card is 24%.
Example B
In the next round of the game, the first person to be dealt a black ace wins the game. You get your first card, and it
is a queen. What is the probability of obtaining a black ace?
Step 1:List what you know.
First event = being dealt the queen
Second event = being dealt the black ace