Answer
$P(club)=0.25$
$P(club~|~black)=0.5$
Work Step by Step
The sample space: all the 52 cards from a standard 52-card deck. So, N(S) = 52.
There are 13 club cards. So N(club) = 13.
We can compute the probability that the card drawn is a club using the Classical Method (see page 259):
$P(club)=\frac{N(club)}{N(S)}=\frac{13}{52}=\frac{1}{4}=0.25$
There are 26 black cards. So, N(black) = 26.
The 13 club cards are black. Now, using the Conditional Probability Rule (see page 288):
$P(club~|~black)=\frac{N(\text{club and black})}{N(black)}=\frac{13}{26}=\frac{1}{2}=0.5$.
