There are a total of 52 cards in a deck. It is divided into 4 suits namely clubs, diamonds, hearts and spades, divided equally among all that is 13 each. Ace consists of one each diamond, spade, club and hearts. Number of spade cards = 13 Number of ace cards = 4 But we have already chosen 1 ace card in the 13 spade cards. Therefor, P{spade or ace} = (13 + 4 - 1)/52 16/52 = 4/13 is the probablity.
