3. (10 Points) Suppose there are B black and R red balls in an urn. A ball is drawn from the urn and discarded; i.e. without replacement. (a) Without knowing its color of the first drawn ball, what is the probability that a second ball drawn is black? You must first describe the sample space. (b) Without knowing the colors of the first two drawn balls, what is the probability that a third ball drawn is black? You must first describe the sample space