If I want to know what the probability is of choosing a queen from a deck of cards given that the previous card was a queen (not replacing the first card in the deck), I think I would use this

$\displaystyle P(A|B) = \frac{P(A \bigcap B)}{P(B)}$

So the probability of B is $\displaystyle \frac{1}{52}$ and the probability of

but how do I work out $\displaystyle P(A \bigcap B)$ ?

thanks

I meant $\displaystyle \frac{4}{52}$