Question
A pack of playing cards was found to contain only 51 cards. If the first 13 cards which are examined are all red, what is the probability that the missing card is black.
Solution
Let E1 the event that the missing card is black and E2 be the event that the missing card is red.
Let A be the event the first 13 cards which are examined are all red.
P(A/E1) = Probability of selecting 13 red cards, when the missing card is black
P(A/E2) = Probability of selecting 13 red cards, when the missing card is red